Doppler sonographic evaluation of resistive index of intra-renal arteries in acute ureteric obstruction.

Background: Acute ureteric colic is one of the most commonly encountered acute abdominal conditions. Diagnosis of obstruction caused by ureteric calculus occasionally becomes challenging if there is inadequate dilation of the urinary tract proximal to obstruction. In such a situation, intra-renal artery Doppler parameters can be used as a diagnostic tool. Our study compared intra-renal arterial Doppler in patients with obstructed and non-obstructed kidneys presenting within 24 h of onset of symptoms of unilateral acute renal colic.

Results: The resistivity index (RI) in the segmental arteries of all 54 patients with obstructed kidneys was significantly higher than in those with non-obstructed kidney: 0.75 vs. 0.56, with a p value less than 0.001, a sensitivity of 85% and a specificity of 93%.

Conclusion: Doppler ultrasound is a useful diagnostic tool in the evaluation of acute renal obstruction, thus enabling practitioners to avoid ordering unnecessary CT and exposing patients to ionizing radiation. An RI value > 0.7 has good sensitivity and specificity in our study. The results obtained in the study were comparable to those of pioneer studies conducted worldwide.