Ultrasonography in pediatric urinary stone diagnosis: clinical utility and diagnostic limitations in light of CT findings
摘要
Ultrasonography (US) is the preferred first-line imaging modality for suspected urinary calculi in children because it is non-invasive and avoids radiation exposure. However, its diagnostic accuracy compared with non-contrast computed tomography (CT) remains variable, depending on stone location and secondary findings. This study evaluated the diagnostic accuracy of US for pediatric urinary calculi, using CT as the reference, and explored the predictive role of secondary sonographic markers.
MethodsWe retrospectively analyzed 47 children (0–18 years) who underwent both US and non-contrast CT for suspected urinary tract calculi (June 2023–2025). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of US were calculated separately for kidney and ureteral calculi. Logistic regression assessed whether hydronephrosis or ureteral dilatation predicted CT-confirmed stones.
ResultsUS showed moderate specificity (84.8%) and NPV (82.4%) overall but limited sensitivity (57.1%) and a high false-negative rate (42.9%) for kidney calculi. Performance was notably poorer for ureteral calculi, with very low sensitivity. Hydronephrosis was significantly associated with ureteral calculi, increasing stone likelihood nearly seven-fold (OR 7.02, 95% CI 1.25–39.40; p = 0.027), while it was not predictive for kidney stones. Ureteral dilatation was not predictive for either kidney (OR 0.34, 95% CI 0.03–3.18; p = 0.349) or ureteral calculi (OR 0.57, 95% CI 0.06–5.41; p = 0.628).
ConclusionsUS remains a valuable first-line tool for pediatric urinary calculi but shows limited sensitivity, particularly for ureteral stones. CT should be reserved for cases with inconclusive or negative US but persistent clinical suspicion or secondary signs suggestive of obstruction, ensuring diagnostic accuracy while minimizing unnecessary radiation exposure.
Graphical abstract