Usefulness of Nonenhanced Computed Tomography for Diagnosing Urolithiasis without Pyuria in the Emergency Department

We compared the clinical utility of nonenhanced computed tomography (NECT) and intravenous urography (IVU) in patients with classic symptoms of renal colic without evidence of a urine infection. This was a retrospective analysis of IVU and NECT performed in adult patients with suspected renal colic at an emergency department between January 2005 and December 2013. The records of all patients in NECT and IVU groups were reviewed, and the patients were categorized according to the cause of their symptoms. A total of 2218 patients were enrolled. Of these patients, 1525 (68.8%) underwent IVU and 693 (31.2%) underwent NECT. The patients in NECT group were older (45.48 +/- 14.96 versus 42.37 +/- 13.68 years, p < 0.001), had less gross hematuria (7.6 versus 2.9%, p < 0.001), and were admitted more often (18.6 versus 12.0%, p < 0.001) than the patients in IVU group. Urinary stones were detected in 1413 (63.7%) patients. NECT had a higher detection rate of urolithiasis than IVP (74.0 versus 59.0%, p < 0.001). No significant difference was observed in the incidence of urinary stones greater than 4 mm between groups from the radiologic findings (p = 0.79) or the full medical record review (p = 0.87).