A novel ultrasonic volumetric flow measurement method using time-domain correlation of consecutive pairs of echoes has been developed. An ultrasonic data acquisition system determined the time shift between a pair of range gated echoes by searching for the time shift with the maximum correlation between the RF sampled waveforms. Experiments with a 5-MHz transducer indicate that the standard deviation of the estimate of steady fluid velocity through 6-mm-diameter tubes is less than 10% of the mean. Experimentally, Sephadex (G-50; 20-80 mu m dia.) particles in water and fresh porcine blood have been used as ultrasound scattering fluids. Two-dimensional (2-D) flow velocity can be estimated by slowly sweeping the ultrasonic beam across the blood vessel phantom. Volumetric flow through the vessel is estimated by integrating the 2-D flow velocity field and then is compared to hydrodynamic flow measurements to assess the overall experimental accuracy of the time-domain method. Flow rates from 50-500 ml/min have been estimated with an accuracy better than 10% under the idealized characteristics used in this study, which include straight circular thin-walled tubes, laminar axially-symmetric steady flow, and no intervening tissues.
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机译：已经开发出一种使用连续回波对的时域相关性的新型超声体积流量测量方法。超声数据采集系统通过搜索在RF采样波形之间具有最大相关性的时移来确定一对距离选通回波之间的时移。用5 MHz传感器进行的实验表明，通过6毫米直径管的稳态流体速度估计值的标准偏差小于平均值的10％。在实验中，水和新鲜猪血中的Sephadex（G-50；直径20-80微米）颗粒已被用作超声散射液。可以通过将超声波束缓慢扫过血管模型来估算二维（2-D）流速。通过对二维流速场进行积分来估算通过容器的体积流量，然后将其与流体动力学流量测量结果进行比较，以评估时域方法的总体实验精度。在本研究中使用的理想特性下，估计流量为50-500 ml / min，其准确性优于10％，这些特性包括直的圆形薄壁管，层流轴对称的稳定流动以及无中间组织。
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