Renal diuretic duplex doppler sonography in childhood hydronephrosis

Objective. The purpose of this study was to determine the diagnostic value of diuretic duplex Doppler sonography in distinguishing between obstructive and nonobstructive hydronephrosis in children by calculating the resistive indices (RI) before and after administration of furosemide. Material and Methods. We prospectively evaluated 28 kidneys (2 solitary) in 15 patients with unilateral or bilateral neonatal hydronephrosis. All pati ents underwent diuretic renography and duplex Doppler sonography before and after administration of furosemide. Results. According to the half-time drainage patterns at diuretic renograph y, 13 kidneys were classified as nonobstructed and 15 as obstructed. At bas eline, the mean RI values of nonobstructed and obstructed kidneys were not significantly different (0.66 and 0.64, respectively). Ten minutes after th e injection of furosemide, the mean RI values of the nonobstructed and obst ructed kidneys were 0.68 and 0.70, respectively. The increase in RI over th e baseline 10 min after the diuretic injection was statistically significan t (p<0.00001) in the obstructed kidneys. Conclusion: The baseline RI value of 0.70 is not a definite value for disti nguishing obstructed from nonobstructed systems. An increase in RI of at le ast 10% over the baseline seems to be a more reliable criterion, especially when it is used in conjunction with diuretic renography.