THE URETERAL JET INDEX - A NOVEL MEASURE OF DIVIDED RENAL-FUNCTION

The aim of this study was to evaluate an index of divided renal functi on based on the quantification of the ureteric jets seen on colour Dop pler ultrasound of the bladder, Thirty-one patients attending for scin tigraphic renography underwent colour Doppler ultrasound with video re cording for 5 min, Divided renal function was calculated as the propor tion of jets from the right-sided orifice ('jet index'), This was comp ared with the corresponding 'scintigraphic index' found using Patlak-R utland graphical analysis, Absolute discrepancies mere calculated, Twe nty-eight of thirty-one (90%) of studies mere diagnostic for the calcu lation of jet indices, The mean jet index was 52% (n=28, SEM=5.8%) com pared to a mean scintigraphic index of 54% (n = 28, SEM = 4.0%), The t wo scores mere correlated, with a correlation coefficient of 0.72 and the median absolute difference between the two scores was 7.7%. Forty- three per cent (12/28) of subjects had discrepancies in the two scores of 5% or less, The score differences, however, showed a highly skewed distribution with 32% (9/28) subjects showing discrepancies over 20%, This discordant group (> 20% difference) included three patients with functional pelviureteric obstruction, one with a pelvic mass and one with an underfilled bladder, Two patients with very poor quality jets had impaired renal function, In one case, the index improved after ang ioplasty for renal artery stenosis, This simple test is a useful adjun ct to urinary tract ultrasound but should be interpreted alongside evi dence of renal obstruction, and complements rather than replaces exist ing tests.