Intrarenal doppler ultrasound versus diuretic renography and pressure flow study [Whitaker test] in obstructed kideny

ABSTRACT

Renal ultrasound examination and intrarenal arterial Doppler studies were performed on 30 patients with urographic evidence of renal obstruction. Renal Doppler ultrasound was compared with both drainage values [T [1/2]] and differential pressure obtained from diuretic renography and Whitaker test respectively, both pre- and post-operatively. Pre-operatively there was close correlation between resistive index [RI] and T [1/2] P<0.001 and also there was close correlation between RI and differential pressure P<0.05. Post-operatively out of the 30 kidneys, 8 still showing obstruction by RI and only one of them had shown obstruction by Whitaker test and 4 showed obstruction by diuretic renography giving us a sensitivity of 25%, specificity of 73.1% for the color Doppler as compared to Whitaker test and sensitivity and specificity of 45%, 81% respectively as compared to diuretic renography. Pre-operatively RI was 0.78 +/- 0.04 and post-operatively RI was 0.65 +/- 0.06 [P<0.001] which was significant Renal Doppler ultrasound correlates closely with both diuretic renography and Whitaker test pre-operatively, but not post-operatively after relief of obstruction, so it can not be used alone in evaluation of obstructive uropathy, but it can be used for follow up of dilated non obstructed system by diuretic renography i.e. non obstructed T [1/2] on a dilated system obviating the need for frequent isotope renography