Temperature dependence of ultrasonic propagation speed and attenuation in excised canine liver tissue measured using transmitted and reflected pulses
Temperature dependence of ultrasonic propagation speed and attenuation in excised canine liver tissue measured using transmitted and reflected pulses
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DOI：
10.1121/1.1738453
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发表时间：
2004-06-01
影响因子：
2.4
通讯作者：
Frank, GR
中科院分区：
文献类型：
--
作者：
Techavipoo, U;Varghese, T;Frank, GR
我们实验室以前的报告数据表明，在25至95 degreesC的离散温度范围内，犬组织在体外的传播速度和衰减的温度依赖性。然而，在整个温度范围内加热相同的组织标本引起了关注，这一过程可能会引起不可逆的，可能是累积的组织降解。本文使用多组样品测量传播速度和衰减随温度的变化，每组样品加热到不同的温度。样品厚度直接测量使用的技术，使用发射和反射的超声波脉冲。使用3和5 MHz中心频率获得的结果表明，在22-60 degreesC范围内传播速度升高约20 m/s，在60-90 degreesC范围内传播速度降低15 m/s，这与之前的结果一致，其中相同的试样经受整个温度范围。然而，这里报道的声速结果略高于以前报道的，可能是由于在本实验中更准确的测量样品厚度。结果还表明，虽然传播速度随温度而变化，但它不是组织凝固的函数。相反，衰减系数取决于组织凝固效应和温度升高。(C)2004年，美国声学学会。
Previous reported data from our laboratory demonstrated the temperature dependence of propagation speed and attenuation of canine tissue in vitro at discrete temperatures ranging from 25 to 95 degreesC. However, concerns were raised regarding heating the same tissue specimen over the entire temperature range, a process that may introduce irreversible and, presumably, cumulative tissue degradation. In this paper propagation speed and attenuation vs temperature are measured using multiple groups of samples, each group heated to a different temperature. Sample thicknesses are measured directly using a technique that uses both transmitted and reflected ultrasound pulses. Results obtained using 3 and 5 MHz center frequencies demonstrate a propagation speed elevation of around 20 m/s in the 22-60 degreesC range, and a decrease of 15 m/s in the 60-90 degreesC range, in agreement with previous results where the same specimens were subjected to the entire temperature range. However, sound speed results reported here are slightly higher than those reported previously, probably due to more accurate measurements of sample thickness in the present experiments. Results also demonstrate that while the propagation speed varies with temperature, it is not a function of tissue coagulation. In contrast, the attenuation coefficient depends on both tissue coagulation effects and temperature elevation. (C) 2004 Acoustical Society of America.