Acute renal colic: diagnosis with duplex Doppler US.

PURPOSE: To determine the sensitivity of renal duplex Doppler sonography in the detection of patients with acute renal colic.

MATERIALS AND METHODS: The authors correlated results of renal duplex Doppler sonography with those of urography in 32 patients presenting with symptoms of urinary colic. The mean resistive index (RI) of each kidney and the difference between the mean RIs (delta RI) of both kidneys were calculated for all patients. The nonpaired two-tailed Student t test was used to determine if there was a significant difference in parameters between patients with and without obstruction. The sensitivity and specificity of the mean RI and the delta RI for the diagnosis of acute renal colic were calculated.

RESULTS: Nineteen patients had obstruction. The differences in the mean RI and delta RI for the patients with and without obstruction were statistically significant. When the published discriminatory thresholds for obstruction (mean RI > or = 0.7, delta RI > or = 0.1) were applied, however, the sensitivity and specificity of the Doppler examination were only 44% and 82%, respectively.

CONCLUSION: Duplex Doppler sonography is highly insensitive for the detection of acute renal colic.