COEFFICIENT OF VARIATION - A POWERFUL DOPPLER ULTRASONOGRAPHIC PARAMETER FOR DETECTION OF RENAL-ARTERY STENOSIS

The aim of our study was to objectively compare the effectiveness of v arious Doppler parameters in the diagnosis of renal artery stenosis. I n three sheep, variable degrees of renal artery stenosis were induced and renal segmental arteries were investigated using pulsed Doppler so nography. In each animal the standard deviation of the instantaneous p eak velocity within one cardiac cycle normalized by the mean peak velo city (coefficient of variation) had significantly higher normalized re gression coefficients (k = -0.215, average of three animals) when com pared to resistive index (k = -0.090) and acceleration index (k* = -0 .069). In each individual animal, coefficient of variation detected lo wer pressure gradients (6.3 mm Hg, average value) than did resistive i ndex (13.4 mm Hg) or accleration index (17.3 mm Hg). The coefficient o f variation may detect the presence of pressure gradients in renal art ery stenosis more accurately than acceleration index or resistive inde x.