Noncontrast helical CT has become the gold standard for the radiologic diagnosis of renal stones. CT can detect almost all stones, evaluate the renal parenchyma, evaluate for urinary tract obstruction, and provide data on surrounding organs.1 Abdominal radiography can identify radiopaque stones but will miss radiolucent stones (eg, uric acid stones) and may miss small stones. Intravenous pyelography has a higher sensitivity and specificity than abdominal radiography for detecting stones and can detect obstruction, but it requires the use of contrast, which can cause adverse reactions. Ultrasonography can detect stones comprised of uric acid and obstruction and is useful in evaluating pregnant women or patients who should avoid radiation. However, ultrasonography can miss stones in the ureter or small stones. Magnetic resonance imaging is not used to diagnose renal stones.
1. Pietrow P, Karellas M. Medical management of common urinary calculi. Am Fam Physician 2006;74:86-94.
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