The Study on the Method of Predicting Renal Function Recoverability of Obstructed Renal Failure with Resistive Index by Two-dimensional Ultrasound

Objective To investigate the predictive effect of the renal resistive index(RI)by ultrasonic measurement to the recoverabilty of renal function in patients with obstructive renal failure and to correlate these values with the corresponding values of serum urea and creatinine and with the recovery of renal function after release of obstruction.Methods A total of 31 patients with obstructive renal failure were evaluated by measurement of RI before release and at 3 days,2 weeks,6 weeks,and 8 weeks after release by color doppler imaging.Serum urea and creatinine were measured at all points of the RI examination.Moreover,RI was measured in an age and sex-matched control group,including 16 healthy volunteers.The patients were classified into two groups according to the recovery of renal function after obstruction were relieved:the first group with significant improvement of serum urea or creatinine and the second with no significant improvement of serum or creatinine.And then the correlation between RI and renal function was analyzed.Results The correlation of RI and BUN、Cr showed that the RI values were highly correlated with renal function.The comparison between the mean RI values of group 1 and group 2 before release showed no significant difference(P0.05).The comparison between the mean RI values before and after release showed significant difference in group 1(P0.05)but no significant difference in group 2(P0.05).The RI value of normal control group is 0.59±0.03,the comparison between the mean RI values of the control group and that of the obstructed patients after release showed no significant difference in group 1,while marked with higher values in group 2.Conclusion Recovery of renal function could not be predicted from the changes in RI before obstruction release.However,a reveral of a previously elevated RI could be used as an early indicator,which is likely to recover renal function.In patients with obstructive nephropathy,the RI has a good positive correlation with serum urea and creatinine.