Characterization of lesion formation and bubble activities during high-intensity focused ultrasound ablation using temperature-derived parameters
Characterization of lesion formation and bubble activities during high-intensity focused ultrasound ablation using temperature-derived parameters
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DOI：
10.1016/j.infrared.2013.04.002
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发表时间：
2013-09-01
影响因子：
3.3
通讯作者：
Deng, Cheri X.
中科院分区：
文献类型：
--
作者：
Hsiao, Yi-Sing;Kumon, Ronald E.;Deng, Cheri X.
成功的高强度聚焦超声（HIFU）热组织消融依赖于组织温度和组织状态的准确信息。温度测量通常用于预测和监测消融过程。在这项研究中，我们进行了高强度聚焦超声消融实验与离体猪心肌组织标本，以确定温度的变化与组织凝固和气泡/空腔形成。使用红外（IR）热成像和同步明场成像，在组织表面附近应用HIFU，从温度时空演变中推导出的参数与HIFU诱导的病变形成和过热相关，后者通常会导致空腔产生和/或组织脱水。首先测量猪心肌的膨胀率为0.857 +/- 0.006（n = 3）。将HIFU结果分为非消融性、正常病变和过热病变。在HIFU应用过程中，观察到损伤形成时温度变化率显著增加。使用温度变化的最大归一化二阶时间导数的标准为损伤识别提供了99.1%的准确度，其中0.05 s（-1）观察到组织表面上的不对称温度分布与过热和/或气泡生成相关。使用峰值温度空间位置的最大位移的标准提供了90.9%的准确度，可以以0.16 mm的阈值识别过热病变。使用红外成像获得的温度的时空演变允许在43摄氏度（CEM 43）的损伤形成的临界累积等效分钟的确定为170分钟。类似的温度特征指示损伤形成和过热被确定为亚表面HIFU消融。这些结果表明，从HIFU应用过程中的温度变化导出的参数与组织中的不可逆变化相关，并可能为监测HIFU治疗提供有用的信息。(C)2013爱思唯尔有限公司版权所有。
Successful high-intensity focused ultrasound (HIFU) thermal tissue ablation relies on accurate information of the tissue temperature and tissue status. Often temperature measurements are used to predict and monitor the ablation process. In this study, we conducted HIFU ablation experiments with ex vivo porcine myocardium tissue specimens to identify changes in temperature associated with tissue coagulation and bubble/cavity formation. Using infrared (IR) thermography and synchronized bright-field imaging with HIFU applied near the tissue surface, parameters derived from the spatiotemporal evolution of temperature were correlated with HIFU-induced lesion formation and overheating, of which the latter typically results in cavity generation and/or tissue dehydration. Emissivity of porcine myocardium was first measured to be 0.857 +/- 0.006 (n = 3). HIFU outcomes were classified into non-ablative, normal lesion, and overheated lesion. A marked increase in the rate of temperature change during HIFU application was observed with lesion formation. A criterion using the maximum normalized second time derivative of temperature change provided 99.1% accuracy for lesion identification with a 0.05 s(-1) Asymmetric temperature distribution on the tissue surface was observed to correlate with overheating and/or bubble generation. A criterion using the maximum displacement of the spatial location of the peak temperature provided 90.9% accuracy to identify overheated lesion with a 0.16 mm threshold. Spatiotemporal evolution of temperature obtained using IR imaging allowed determination of the critical cumulative equivalent minutes at 43 degrees C (CEM43) for lesion formation to be 170 min. Similar temperature characteristics indicative of lesion formation and overheating were identified for subsurface HIFU ablation. These results suggest that parameters derived from temperature changes during HIFU application are associated with irreversible changes in tissue and may provide useful information for monitoring HIFU treatment. (C) 2013 Elsevier B.V. All rights reserved.