THE INTRARENAL RESISTIVE INDEX AS A PATHOPHYSIOLOGICAL MARKER OF OBSTRUCTIVE UROPATHY

PURPOSE: The intrarenal resistive index is a physiological parameter that indirectly reflects the degree of resistance in the intrarenal vasculature. Resistive index measurements have been advocated for the diagnostic evaluation of several renal pathologies, including obstructive uropathy. However, despite extensive research in this field during the last decade clear guidelines on the use of resistive index measurements for discriminating obstructive from nonobstructive dilatation of the upper urinary tract remain elusive. Therefore, we reviewed the literature to clarify the proper role of resistive index measurements in the context of obstructive uropathy. MATERIALS AND METHODS: We reviewed the recent literature on the use of resistive index measurements for the diagnostic evaluation of obstructive uropathy. RESULTS: Despite a continuously growing body of literature the resistive index has yet to be recognized as a dependable parameter when it comes to resolving the long-standing dilemma of the dilated upper urinary tract. While proponents have observed that this method has sensitivity and specificity that supersede those of conventional methods, opponents have reported that the resistive index is an unreliable parameter that is prone to systemic and local influences. CONCLUSIONS: Resistive index measurements are still in a developmental phase. Additional studies are needed before this technique may be used reliably for the diagnosis of obstructive uropathy.