ABSTRACT
PURPOSE: This study was performed to compare the accuracy of noncontrast helical computerized tomography (NHCT) with that of intravenous pyelography (IVP) in the evaluation of urolithiasis in the emergency room (ER). METHODS: Between November 2003 and February 2004, a total of 47 consecutive patients presenting to the emergency department with acute flank pain were evaluated with NHCT followed by IVP. The mean of the time interval between NHCT and IVP was less than 5 minutes. All 47 sets of evaluations were later assessed randomly by an independent consulting radiologist for the presence, size, and location of a stone, ureteral dilatation, and secondary signs of ureteral obstruction. RESULTS: Forty-three of the 47 patients were diagnosed with urolithiasis. In 39 of the 43 patients diagnosed with ureteral calculi, the NHCT made the diagnosis. IVP made the diagnosis in 26 of the 43 patients. NHCT had a 90.7% sensitivity, 100% specificity, and 68% accuracy. Compared with IVP, using the McNemar test, NHCT was significantly better able to predict the presence of urolithiasis (p<0.001). CONCLUSIONS: Unnenhanced helical CT is superior to IVP in the demonstration of ureteral calculi in patients with suspected acute urolithiasis in the ER.