PREDICTIVE ACCURACY OF RENAL ULTRASOUND AND MAG3 SCINTIGRAPHY IN GUIDING SURGERY AND MONITORING RECOVERY IN PEDIATRIC PUJO: A PROSPECTIVE COHORT STUDY

Abstract

Introduction: Pelviureteric junction obstruction (PUJO) is the most common cause of congenital hydronephrosis. Differentiating which children require surgical correction and which can be managed conservatively remains a diagnostic challenge. This study aimed to evaluate the predictive accuracy of renal ultrasound and MAG3 scintigraphy in guiding surgical decision-making and monitoring outcomes in pediatric PUJO. Materials and Methods: This prospective cohort study included 80 children with suspected PUJO who underwent renal ultrasound and MAG3 diuretic renography. Surgery was offered only to patients with an anteroposterior (AP) pelvic diameter >20 mm and an obstructive drainage curve (T½ >20 minutes). Intraoperative and histopathological confirmation of PUJO was obtained in surgically managed cases. Postoperative and conservatively managed patients were followed with imaging at 3, 6, and 9 months. Comparative statistical analysis and visualizations were used to assess differences between groups. Results: Thirty-nine patients fulfilled the surgical criteria and underwent pyeloplasty. Intraoperative findings and histology confirmed PUJO in all cases. Postoperatively, mean AP diameter reduced from 25.6 mm to 14.8 mm, and differential renal function (DRF) improved or stabilized in 94% of cases. Among the 41 non-surgical patients, 81% showed spontaneous reduction in AP diameter and all maintained stable DRF. A statistically significant difference in AP diameter was observed between obstructive and non-obstructive groups (p < 0.0001), supported by both box plot and density curve visualizations. Conclusion: An AP diameter >20 mm combined with an obstructive drainage pattern on MAG3 renography provides a highly specific and sensitive criterion for identifying children with PUJO who require surgical intervention. Children not meeting both criteria can be safely observed, with excellent outcomes. This dual-modality imaging strategy should serve as a cornerstone in PUJO management protocols.