Journal of Ultrasound in Medicine, Vol 14, Issue 12 939-947, Copyright © 1995 by American Institute of Ultrasound in Medicine
In vitro and in vivo validation of time domain velocity and flow measurement technique
D. Maulik, T. Kadado, G. Downing and C. Phillips
Department of Obstetrics and Gynecology, University of Missouri-Kansas City School of Medicine, Kansas City, USA.
This study was undertaken to validate the time domain processing method for
measuring (1) the peak velocity in comparison to pulsed-wave spectral
Doppler findings in an in vitro system; (2) the volumetric flow in
comparison to the actual flow measured by a graduated cylinder in an in
vitro circulation; and (3) the volumetric flow in comparison to a transit
time flowmeter in a permanently instrumented neonatal lamb model. A
prototype implementation of time domain processing in a commercial
ultrasound device was used. For velocimetry, both time domain processing
and Doppler methods showed low variance, low intrarater variability (0.03
and 0.09%, respectively), high reliability coefficients (97% and 96%,
respectively), and a significant correlation (r = 0.96; P < 0.001). For
in vitro flow quantification, time domain processing and graduated cylinder
methods showed low variance, low intrarater variability (0.09 and 0.01%,
respectively), high reliability coefficients (99.60% and 99.96%,
respectively), and a significant correlation (r = 0.98, P < 0.001). For
in vivo flow quantification, time domain processing and transit time
flowmeter showed a significant correlation (r = 0.96; P < 0.001). Within
the limits of the in vitro and in vivo experimental conditions, this study
proves the validity of the time domain processing sonographic technique for
measuring peak flow velocity and volumetric flow.