Zhang Siyuan, Han Yuqiang, Zhu Xingguang, Shang Shaoqiang, Huang Guojing, Zhang Lei, Niu Gang, Wang Supin, He Xijing, Wan Mingxi
Key Laboratory of Biomedical Information Engineering, Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China.
Department of Radiology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
Ultrasound Med Biol. 2017 Feb;43(2):482-493. doi: 10.1016/j.ultrasmedbio.2016.10.003. Epub 2016 Nov 25.
The feasibility of using ultrasonic Nakagami imaging to evaluate thermal lesions induced by microwave ablation (MWA) in ex vivo porcine liver was explored. Dynamic changes in echo amplitudes and Nakagami parameters in the region of the MWA-induced thermal lesion, as well as the contrast-to-noise ratio (CNR) between the MWA-induced thermal lesion and the surrounding normal tissue, were calculated simultaneously during the MWA procedure. After MWA exposure, a bright hyper-echoic region appeared in ultrasonic B-mode and Nakagami parameter images as an indicator of the thermal lesion. Mean values of the Nakagami parameter in the thermal lesion region increased to 0.58, 0.71 and 0.91 after 1, 3 and 5 min of MVA. There were no significant differences in envelope amplitudes in the thermal lesion region among ultrasonic B-mode images obtained after different durations of MWA. Unlike ultrasonic B-mode images, Nakagami images were less affected by the shadow effect in monitoring of MWA exposure, and a fairly complete hyper-echoic region was observed in the Nakagami image. The mean value of the Nakagami parameter increased from approximately 0.47 to 0.82 during MWA exposure. At the end of the postablation stage, the mean value of the Nakagami parameter decreased to 0.55 and was higher than that before MWA exposure. CNR values calculated for Nakagami parameter images increased from 0.13 to approximately 0.61 during MWA and then decreased to 0.26 at the end of the post-ablation stage. The corresponding CNR values calculated for ultrasonic B-mode images were 0.24, 0.42 and 0.17. This preliminary study on ex vivo porcine liver suggested that Nakagami imaging have potential use in evaluating the formation of MWA-induced thermal lesions. Further in vivo studies are needed to evaluate the potential application.
探讨了使用超声中谷成像评估体外猪肝中微波消融（MWA）诱导的热损伤的可行性。在MWA过程中，同时计算MWA诱导的热损伤区域的回波幅度和中谷参数的动态变化，以及MWA诱导的热损伤与周围正常组织之间的对比噪声比（CNR）。MWA暴露后，超声B模式和中谷参数图像中出现明亮的高回声区域，作为热损伤的指标。MVA 1、3和5分钟后，热损伤区域中谷参数的平均值分别增加到0.58、0.71和0.91。不同MWA持续时间后获得的超声B模式图像中，热损伤区域的包络幅度没有显著差异。与超声B模式图像不同，中谷图像在监测MWA暴露时受阴影效应的影响较小，并且在中谷图像中观察到相当完整的高回声区域。在MWA暴露期间，中谷参数的平均值从约0.47增加到0.82。在消融后阶段结束时，中谷参数的平均值降至0.55，高于MWA暴露前的值。中谷参数图像计算的CNR值在MWA期间从0.13增加到约0.61，然后在消融后阶段结束时降至0.26。超声B模式图像计算的相应CNR值分别为0.24、0.42和0.17。这项对体外猪肝的初步研究表明，中谷成像在评估MWA诱导的热损伤形成方面具有潜在用途。需要进一步的体内研究来评估其潜在应用。
