MEASUREMENTS OF ULTRASONIC PULSE ARRIVAL TIME AND ENERGY-LEVEL VARIATIONS PRODUCED BY PROPAGATION THROUGH ABDOMINAL-WALL
MEASUREMENTS OF ULTRASONIC PULSE ARRIVAL TIME AND ENERGY-LEVEL VARIATIONS PRODUCED BY PROPAGATION THROUGH ABDOMINAL-WALL
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DOI：
10.1121/1.408347
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发表时间：
1994-01-01
影响因子：
2.4
通讯作者：
WAAG, RC
中科院分区：
文献类型：
--
作者：
HINKELMAN, LM;LIU, DL;WAAG, RC
测量了超声脉冲通过人体腹壁标本传播所带来的到达时间和能级变化。半球形换能器传输超声脉冲，该脉冲通过腹壁切片后被线性阵列换能器检测到。该阵列在仰角方向上平移，以在二维孔径上收集数据。测量波形与计算参考之间的到达时间和能级差异是造成几何延迟和扩散的原因。补偿几何路径的波形图、时间延迟差异和能量水平波动图以及由此得出的水路径和组织路径的统计数据表征了测量系统，并描述了14种不同人体腹壁标本引起的时间延迟差异和能量水平波动。使用相同标本的重复测量表明，单个组织路径测量是可重复的，结果取决于标本的位置，并且标本冷冻保存三个月似乎不会改变标本产生的时间延迟差异和能级波动。在室温和体温下的测量结果比较表明，在体温下发生明显较大的时间延迟差异，而能量水平波动和时间延迟差异模式受影响较小。对于14个不同腹壁标本，时间延迟差和能级波动的均方根分别为43.0 ns和3.30 dB，时间延迟差和能级波动的相关长度分别为7.90和2.28 mm。接收面时延差与能级波动的空间格局基本不相关，但能级波动的一些背景变化与时延差图的特征相似。结果为超声前到达的变化和范围以及通过腹壁传播引起的能量变化提供了重要的新信息。
Ultrasonic pulse arrival time and energy level variations introduced by propagation through human abdominal wall specimens have been measured. A hemispheric transducer transmitted an ultrasonic pulse that was detected by a linear array transducer after propagation through an abdominal wall section. The array was translated in the elevation direction to collect data over a two-dimensional aperture. Differences in arrival time and energy level between the measured waveforms and calculated references that account for geometric delay and spreading were found. Plots of waveforms compensated for geometric path, maps of time delay differences and energy level fluctuations, and statistics derived from these for water paths and tissue paths characterize the measurement system and describe the time delay differences and energy level fluctuations caused by 14 different human abdominal wall specimens. Repeated measurements using the same specimens show that individual tissue path measurements are reproducible, the results depend on specimen position, and frozen storage of a specimen for three months does not appear to alter the time delay differences and energy level fluctuations produced by the specimen. Comparison of measurements at room and body temperature indicates that appreciably higher time delay differences occur at body temperature while energy level fluctuations and time delay difference patterns are less affected. For the 14 different abdominal wall specimens, the rms time delay differences and energy level fluctuations have average values of 43.0 ns and 3.30 dB, respectively, and the associated correlation lengths of the time delay differences and energy level fluctuations are 7.90 and 2.28 mm, respectively. The spatial patterns of time delay difference and energy level fluctuation in the reception plane appear largely uncorrelated, although some background variations in energy level fluctuation are similar to features in time delay difference maps. The results provide important new information about the variety and range of ultrasonic wave front arrival and energy variations caused by transmission through abdominal wall.