POTENTIAL ROLE OF DUPLEX-DOPPLER SONOGRAPHY IN ACUTE RENAL COLIC

Purpose. We assessed the value of renal duplex Doppler sonography in d iagnosing obstruction in patients with acute renal colic. Methods. We compared the results of renal duplex Doppler sonography with those of intravenous urography (IVU) in 65 patients presenting with symptoms of renal colic. The Doppler spectral waveforms were used to calculate th e resistance index (RI). The difference between the mean Rls (Delta RI ) in the 2 kidneys was calculated for each patient. The sensitivity, s pecificity, and accuracy of Delta RI for the diagnosis of obstruction were calculated with several discriminatory thresholds. Results. All p atients had an obstruction on IVU. When a high Delta RI threshold for obstruction (Delta RI greater than or equal to 0.1) was applied, the s ensitivity and specificity of duplex Doppler sonography were 10% and 8 0%, respectively. When the Delta RI threshold was decreased, the sensi tivity increased but the specificity decreased, and both remained quit e low. Twelve patients had a lower mean RI in the obstructed kidney th an in the normal contralateral kidney. Among 14 patients without pyelo caliceal dilatation, the sensitivity of duplex Doppler sonography was 70% with a Delta RI threshold of 0.03. Conclusions. Duplex Doppler son ography is not sensitive enough to diagnose obstruction in patients wi th acute renal colic. (C) 1998 John Wiley & Sons, Inc.