Journal of Ultrasound in Medicine, Vol 15, Issue 7 505-512, Copyright © 1996 by American Institute of Ultrasound in Medicine
Coefficient of variation: a powerful Doppler ultrasonographic parameter for detection of renal artery stenosis
K. Eibenberger, H. Schima, W. Trubel, T. Temel, C. Schmidt, R. Scherer, U. Windberger, W. Dock and F. Grabenwoger
Department of Radiology, University of Vienna, Austria.
The aim of our study was to objectively compare the effectiveness of
various Doppler parameters in the diagnosis of renal artery stenosis. In
three sheep, variable degrees of renal artery stenosis were induced and
renal segmental arteries were investigated using pulsed Doppler sonography.
In each animal the standard deviation of the instantaneous peak velocity
within one cardiac cycle normalized by the mean peak velocity (coefficient
of variation) had significantly higher normalized regression coefficients
(k* = -0.215, average of three animals) when compared to resistive index
(k* = -0.090) and acceleration index (k* = -0.069). In each individual
animal, coefficient of variation detected lower pressure gradients (6.3 mm
Hg, average value) than did resistive index (13.4 mm Hg) or acceleration
index (17.3 mm Hg). The coefficient of variation may detect the presence of
pressure gradients in renal artery stenosis more accurately than
acceleration index or resistive index.
