首页   按字顺浏览 期刊浏览 卷期浏览 Measurements of ultrasonic pulse arrival time and energy level variations produced by p...
Measurements of ultrasonic pulse arrival time and energy level variations produced by propagation through abdominal wall

 

作者: Laura M. Hinkelman,   Dong‐Lai Liu,   Leon A. Metlay,   Robert C. Waag,  

 

期刊: The Journal of the Acoustical Society of America  (AIP Available online 1994)
卷期: Volume 95, issue 1  

页码: 530-541

 

ISSN:0001-4966

 

年代: 1994

 

DOI:10.1121/1.408347

 

出版商: Acoustical Society of America

 

关键词: ULTRASONIC WAVES;PULSE PROPAGATION;TIME DELAY;WAVE FORMS;FLUCTUATIONS;TISSUES;ABDOMEN

 

数据来源: AIP

 

摘要:

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.

 

点击下载:  PDF (2009KB)



返 回