Comparison of intravenous urography and magnetic resonance urography to assess congenital anomalies of the kidney and urinary tract

Background: Congenital anomalies of the kidneys and urinary tract (CAKUT) are major causes of pediatric renal morbidity and chronic kidney disease. While intravenous urography (IVU) is widely used, magnetic resonance urography (MRU) offers radiation-free anatomical and functional evaluation. Aims and Objectives: This study aimed to compare the diagnostic performance, accuracy, and clinical utility of MRU and IVU in pediatric patients with CAKUT and to identify the modality that provides better anatomical and functional assessment for appropriate management planning. Materials and Methods: This prospective comparative study included 75 children aged 0–12 years with suspected obstructive uropathy. All patients underwent ultrasonography, IVU, and MRU. MRU findings were considered the reference standard. Diagnostic superiority was assessed based on lesion detection, anatomical clarity, and functional information. Statistical analyses were performed using the Chi-square and Fisher’s exact tests, with P<0.05 considered significant. Results: Among the patients, 64% were male, and the mean age was 4.68±1.95 years. Antenatal hydronephrosis (45.33%) was the most common presentation. A duplex kidney was the most frequent anomaly (36%). MRU demonstrated overall diagnostic superiority in 72% of cases. It showed significantly better detection of multicystic dysplastic kidneys (100%), megaureters (100%), non-functioning/non-opacified kidneys (100%), and improved characterization of duplex systems and hydronephrosis (P<0.001). MRU was significantly more beneficial in children >5 years (P=0.02) and in those referred following antenatal detection of renal agenesis or postnatal urinary tract infection. No superiority was observed in ectopic kidneys or selected pelviureteric junction obstruction cases. Conclusion: MRU provides superior diagnostic accuracy and clinical utility compared with IVU and should be preferred for the comprehensive evaluation of pediatric CAKUT, particularly for complex anomalies requiring combined structural and functional assessment.