Role of rezistive index in evaluation of obstruktive and nonobstruktive uropathy

Clinical studies using Doppler sonography identified an alteration in renal arterial blood flow in obstructed hydronephrotic kidneys. This can be used to distinguish obstructive from nonobstructive collecting system dilatation.From 2009 through 2010 we attempted to measure as retrospectıve the rezistive index (Rİ) in all patients with acut urinary tract obstruction who presented to our emergency department. The contralateral nonobstructed kidneys served as controls. Criteria for obstruction were a Rİ of 0,70 or greater and/or a side tos ide difference of 0,08 or greater.We evaluated 61 patients %78,6 (n:48) of them had Rİ values greater than 0,70 and the differences of Rİ values between two kidneys (?Rİ) were greater than 0,08. In 6 patients, Rİ values were between 0,61 and 0,70 but also the differences between two kidneys were smaller than 0,08. In 7 patients, Rİ values were smaller than 0,70 but side tos ide differences were greater than 0,08.When we evaluated these patients with ultrasonography and/or IVP, %90 (n=55) of them had urınary tract obstruction. Overall, as compared with Rİ values, diagnostic accuracy rate was %100.This study supplements the existing evidence that, in acutely obstructed kidneys, renal Doppler recording can demonstrate altered renal perfusion before pelvicalyceal system dilatation and distinguish obstructed and unobstructed kidneys evaluated with suspicion of renal colic.Key words: Renal obstruction, Doppler ultrasonography, Resistive index