On the thermal effects associated with radiation force imaging of soft tissue
On the thermal effects associated with radiation force imaging of soft tissue
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DOI：
10.1109/tuffc.2004.1320828
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发表时间：
2004-05-01
影响因子：
3.6
通讯作者：
Nightingale, KR
中科院分区：
文献类型：
--
作者：
Palmeri, ML;Nightingale, KR
一些实验室正在研究使用声辐射力对组织的机械特性进行成像。声辐射力脉冲 (ARFI) 成像是一种使用短暂、高强度、聚焦的超声脉冲在组织中产生辐射力的方法。这种辐射力产生组织位移，可以使用传统的基于相关性的超声方法来跟踪该位移。组织响应提供了一种辨别组织机械特性的机制。组织吸收的声能产生辐射力和组织加热。已经开发了声加热的有限元方法模型，该模型可以模拟短时辐射力施加期间不同组织的热响应。本文对 ARFI 成像期间使用的光束序列和焦点配置进行了建模；这些热模型的结果可以扩展到由于与其他基于辐射力的成像模式相关的吸收而产生的加热。 ARFI 包含的热扩散率模式是换能器 f 数、组织吸收以及相邻 ARFI 询问的时间和空间间隔的函数。冷却时间常数约为几秒。对于 ARFI 成像来说，热膨胀引起的组织位移可以忽略不计。由于温度变化而引起的声速变化可能是明显的。这些热模型表明，软组织的 ARFI 成像是安全的，尽管在开发 ARFI 光束序列时必须监测热响应。
Several laboratories are investigating the use of acoustic radiation force to image the mechanical properties of tissue. Acoustic Radiation Force Impulse (ARFI) imaging is one approach that uses brief, high-intensity, focused ultrasound pulses to generate radiation force in tissue. This radiation force generates tissue displacements that are tracked using conventional correlation-based ultrasound methods. The tissue response provides a mechanism to discern mechanical properties of the tissue.The acoustic energy that is absorbed by tissue generates radiation force and tissue heating. A finite element methods model of acoustic heating has been developed that models the thermal response of different tissues during short duration radiation force application. The beam sequences and focal configurations used during ARFI imaging are modeled herein; the results of these thermal models can be extended to the heating due to absorption associated with other radiation force-based imaging modalities. ARFI-incluced thermal diffusivity patterns are functions of the transducer f-number, the tissue absorption, and the temporal and spatial spacing of adjacent ARFI interrogations. Cooling time constants are on the order of several seconds. Tissue displacement due to thermal expansion is negligible for ARFI imaging. Changes in sound speed due to temperature changes can be appreciable. These thermal models demonstrate that ARFI imaging of soft tissue is safe, although thermal response must be monitored when ARFI beam sequences are being developed.