Doppler ultrasonography in evaluation of renal hemodynamics in hydronephrosis in children

Resistence index (RI) measurement by the Doppler sonography is a noninvasive diagnostic method which was introduced in the diagnosis of hydronephrosis in children in 1989. In 1991 Palmer modified this method by administering furosemide (Diuretic Doppler ultrasonography) in order to distinguish an obstructional and nonobstructional dilatation of the upper urinary tract. The method is based on the fact that an obstruction of the upper urinary tract results in increasing of the intrarenal arterial resistence and therefore in decreasing of vascular flow. RI value shows the importance of obstruction. The authors performed this method on 37 children aged 2 to 16, 12 children with a significant ureteropelvic obstruction, 15 children with a nonsignificant obstruction (hydronephrosis of grades I-II and persisting dilatation of the ureteropelvic system after pyeloplasty); the control group consisted of 10 children with normal sonography and scintigraphy findings in the kidneys. The results were compared to the results of dynamic scintigraphy -99m Tc DTPA with furosemide. Elevation of RI values in clinically significant hydronephrosis was proved. The authors see the utility of Doppler ultrasonography as being in the diagnosis of nonsignificant obstructions, in the screening of children with ureteropelvic system dilatation, and in follow-up examinations of children after pyeloplasty.