STONE is a multicenter, randomized controlled trial of ultrasonography versus computed tomography (CT) for the initial evaluation of patients with suspected urolithiasis seen in urban emergency departments (EDs). Patients with suspected urolithiasis will be recruited from 15 large urban medical centers and randomized to one of three study arms: (1) ultrasonography in the ED; (2) ultrasonography in radiology; and (3) CT in radiology. Patients will be followed for six months following the ED visit, and a range of outcomes will be measured to allow assessment of effectiveness, safety, accuracy, and cost as they vary by the group to which patients were assigned.
