VALUE OF RENAL DOPPLER US FOR THE DIAGNOS IS OF ACUTE OBSTRUCTION OF THE UPPER URINARY-TRACT

A comparative study of the resistivity indices (RI) obtained in both k idneys has been carried out in 30 controls and 60 patients with suspec ted unilateral acute obstruction of the upper urinary tract. Doppler f indings (difference in the mean RI of both kidneys, DELTA RI) in the p athologic population have been systematically correlated to the data y ielded by intravenous pyelography (IVP). In the control population DEL TA RI was always less-than-or-equal-to 0.03 (mean DELTA RI = 0.01, SD = 0.01). Considering that an increase in DELTA RI greater-than-or-equa l-to 0.05 (>mean RI + 3 SD) is significant, 93% sensitivity and 100% s pecificity are obtained for the diagnosis of unilateral acute obstruct ion. Comparison of the resistivity indices of both kidneys is more spe cific and more sensitive than the assessment of the index on the obstr ucted side only; it improves the performance of ultrasonography in the initial diagnosis of acute urinary tract obstruction.