Doppler studies in normal kidneys of healthy children.

Despite the widespread use of Doppler ultrasound in kidney diseases of adults and children, there are only a few, partially contradictory reports of normal values of resistance index (RI) and pulsatility index (PI) of renal perfusion in a healthy pediatric population. This study was carried out to determine normal values for these parameters in a larger group of probands. For the RI correlation with age was most pronounced in the right renal artery, with children over 6 years having a significantly lower RI than younger children. The PI was relatively independent of side and age. These results are somewhat different to previous reports. These differences may influence future Doppler sonographic investigations of acute and symmetrically affected kidneys (nephrological diseases). Our data suggest that the RI of the right renal artery might be most useful. In chronical or unilateral kidney diseases (unilateral ureteral obstruction, reflux, or operation) investigation of the PI in addition to the RI may aid diagnosis.