Diagnostic value of post-furosemide ultrasonography in children with pelvicalyceal dilatation (renal pelvis APD 10–20 mm): a predictor of pyeloplasty indication and comparison with diuretic renal scintigraphy

Abstract Background Borderline pelvicalyceal dilatation in children (renal pelvis APD 10–20 mm) poses a diagnostic challenge in determining which cases require surgical intervention. Diuretic renal scintigraphy (DRS) is the current standard but is not always accessible. A reliable, non-invasive alternative is needed. This study aimed to evaluate the diagnostic value of post-furosemide ultrasonography in children with borderline anteroposterior diameter (APD) and to compare its performance with diuretic renal scintigraphy and surgical outcomes. Methods In this prospective diagnostic study, 55 children with suspected ureteropelvic junction obstruction (UPJO) and APD between 10 and 20 mm underwent renal ultrasound before and after intravenous furosemide injection. Anteroposterior diameter (APD) and resistive index (RI) were measured at baseline and at 18 and 30 min post-injection. Results were compared with DRS and subsequent surgical decisions. Results Children with UPJO had significantly higher APD and RI values at all post-furosemide intervals ( p < 0.05). APD ≥ 11.5 mm and RI increase > 0.735 at 30 min showed high diagnostic accuracy for UPJO (AUC = 0.951 and 0.975, respectively). An APD of ≥ 29.5 mm predicted the need for pyeloplasty with 83.3% sensitivity and 95.9% specificity. Conclusions Post-furosemide ultrasonography is a practical and accurate method for identifying true obstruction and predicting surgical need in children with borderline hydronephrosis. It may serve as a reliable alternative to DRS, particularly in resource-limited settings.