AJP - Heart and Circulatory Physiology, Vol 247, Issue 5 847-H856, Copyright © 1984 by American Physiological Society
Validation of a third-generation Doppler system for studies of detailed aortic flow
J. A. Rumberger, C. F. Fastenow, D. L. Laughlin and M. L. Marcus
A multigated, third-generation Doppler velocity system has been developed
and validated for detailed studies of aortic hemodynamics. The Doppler
system employs a single 3-mm, 5-MHz crystal applied to the aorta at a fixed
angle with respect to the flow axis and is capable of measuring velocity
profile, blood vessel diameter, and integrated volume flow on a continuous,
real-time basis. This represents a major developmental advance over
existing first-generation, continuous-wave and second-generation,
single-gated pulsed Doppler systems. Validation studies have been performed
in vitro and in dogs. Aortic diameter was measured simultaneously with the
volumetric Doppler system and with sonomicrometer probes. During changes in
aortic diameter between 8 and 18 mm (n = 18), produced by temporary
pulmonary artery occlusion or epinephrine infusion, quantitative agreement
between the Doppler and sonomicrometer probes was found (r = 0.96).
Velocity profile measurements and axial velocity values made with the
Doppler system compared favorably with hot-film anemometry studies in vitro
and in vivo. Although the current system is nondirectional, measurements of
phasic aortic volume flow and absolute-time-averaged changes in flow rates
showed an excellent correlation with chronically placed electromagnetic
flow probes over a broad range of flow rates in vivo (1-5 l/min, n = 36, r
= 0.95). This third-generation Doppler system should prove useful in
clinical and research studies of detailed aortic hemodynamics.
