Imaging of flank pain: readdressing state-of-the-art.

Pain resulting from renal and ureteral stones is a common cause for patients presenting in the acute setting. Since the late 1990s, computed tomography (CT) has been the initial imaging method of choice to evaluate patients with suspected ureteral stones; however, concerns regarding both radiation dose and cost-effectiveness have prompted investigations into a different imaging algorithm. Studies utilizing ultrasound have provided evidence indicating that it may be a more appropriate first step, with selective use of CT in selected cases, in the diagnostic work-up. Techniques have evolved with low-dose CT, dual-energy CT, and magnetic resonance urography emerging as useful in imaging of renal colic patients. This manuscript reviews the current literature on state-of-the-art imaging for acute flank pain and proposes a new imaging algorithm in the evaluation of patients with acute flank pain and suspected ureteral stones.