Diuretic Doppler sonography in postnatal hydronephrosis.

Renal resistive indexes were measured by Doppler sonography in 12 children undergoing other standard diagnostic studies to evaluate hydronephrosis. Measurement of renal resistive indexes was modified by prior placement of a bladder catheter, oral hydration and administration of 1 mg./kg. furosemide after baseline measurement. Renal resistive indexes were again measured at 10 and 30 minutes after diuretic. While diuretic administration had no measurable influence on 10 nonobstructed kidneys, the elevated 10-minute post-diuretic renal resistive indexes recorded in 10 obstructed kidneys differed significantly from the indexes recorded in the nonobstructed group (p less than 0.001). The highest elevations in renal resistive indexes were recorded in nonpaired kidneys, which included 7 of the 10 kidneys in the obstructed group. In the 3 unilaterally obstructed kidneys the 10-minute post-diuretic renal resistive indexes did not differ significantly. However, renal resistive indexes in these kidneys increased at least 15% over baseline readings after diuretic administration. Diuretic Doppler sonography appears to be another useful method for differentiating functionally significant hydronephrosis from nonobstructive hydronephrosis in children.