Impact of gas bubbles generated during interstitial ablation on elastographic depiction of in vitro thermal lesions
Impact of gas bubbles generated during interstitial ablation on elastographic depiction of in vitro thermal lesions
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DOI：
10.7863/jum.2004.23.4.535
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发表时间：
2004-04-01
影响因子：
2.3
通讯作者：
Lee, FT
中科院分区：
文献类型：
--
作者：
Varghese, T;Techavipoo, U;Lee, FT
客观的。射频消融过程中气泡形成的伪影以及正常区域和治疗区域（坏死区）之间较差的内在对比度对于传统超声检查中坏死区域的可视化来说是相当大的问题。超声弹性成像对于坏死区域的可视化非常有效，但它使用与形成灰度图像相同的回波信号来估计应变。因此，必须研究气泡对应变图像或弹性图的影响。方法。在体外对肝脏组织样本进行射频消融，样本大小约为 40 x 40 x 20 毫米，封装在 80 毫米立方明胶模型中。在具有 5 MHz 线性阵列的实时扫描仪上获得了消融过程中不同时刻生成的弹性图。弹性图序列说明了热损伤的生长。结果。观察到热损伤远端边界的退化。退化仅限于热损伤的下第五象限。然而，仍然可以通过外推热损伤边界来获得对损伤区域的准确估计。结论。射频消融过程中可以获得体外热损伤的弹性图。在由于气泡引起的衰减降低了回波信号的信噪比的区域中观察到应变图像上热损伤边界信息的一些丢失。
Objective. Artifacts from gas bubble formation during radio frequency ablation along with the poor intrinsic contrast between normal and treated regions (zone of necrosis) are considerable problems for the visualization of the necrotic region on conventional sonography. Sonographic elastography is very effective for visualizing the zone of necrosis, but it uses the same echo signals to estimate strain as those used to form gray scale images. Thus, the impact of gas bubbles on strain images or elastograms must be investigated. Methods. Radio frequency ablation was performed in vitro on liver tissue samples, approximately 40 x 40 x 20 mm, encased in 80-mm cubed gelatin phantoms. Elastograms generated at different instants during the ablation procedures were obtained on a real-time scanner with a 5-MHz linear array. Sequences of elastograms illustrate the growth of the thermal lesion. Results. Degradation of the distal boundary of the thermal lesion was observed. The degradation was confined to the lower-fifth quadrant of the thermal lesion. However, accurate estimates of lesion areas could still be obtained by extrapolation of the thermal lesion boundary. Conclusions. Elastograms of thermal lesions in vitro can be obtained during radio frequency ablation. Some loss of thermal lesion boundary information on strain images was observed in regions where attenuation due to gas bubbles reduced the signal-noise ratio of the echo signals.