[Evaluation of blood flow in the renal artery and intraparenchymal arteries in neonates using color doppler sonography].

The authors examined 25 kidneys in 14 healthy neonates in order to evaluate the resistive index (RI) calculated from the maximal systolic and end-diastolic rate of blood flow in the renal artery and some intraparenchymatous arteries. They revealed a significant drop of all absolute rates of blood flow in arteries in the direction to the renal periphery. Consistent with rather few data in the literature, they assessed a normal RI value of intraparenchymatous arteries in healthy neonates (0.76 +/- 0.04) which differs significantly from values assessed in the renal artery (0.82 +/- 0.05) (p < or = 0.001). The authors discuss the normal RI value in the neonatal period. In the conclusion they mention that the RI can be obtained much more easily from the blood flow in the renal artery than the blood flow in intraparenchymatous arteries but the former does not reflect representatively the intraparenchymatous conditions in the kidneys and this restricts its use in evaluations of intraparenchymatous renal processes.