Distinction between obstructive and nonobstructive hydronephrosis: value of diuresis duplex Doppler sonography.

The purpose of this study was to determine the diagnostic accuracy of diuresis duplex Doppler sonography in distinguishing between obstructive and nonobstructive hydronephrosis by calculating the resistive indexes before and after administration of furosemide.We prospectively studied 48 kidneys in 26 patients with suspected chronic renal obstruction. All patients underwent diuretic renography and duplex Doppler sonography before and after administration of furosemide. According to the findings at diuretic renography, kidneys were classified as nonobstructed (n = 12), indeterminate (n =9), obstructed (n = 8), or normal (n = 19). The mean resistive index of each kidney and the difference between the mean resistive indexes of both kidneys were calculated before and after administration of 0.5 mg furosemide per kilogram of body weight. A receiver operating characteristic curve was generated to determine the discriminatory resistive index value for diagnosing obstruction.Resistive indexes were not significantl...