Efficacy of magnetic resonance urography in detecting renal scars in children with vesicoureteral reflux.

BACKGROUND: The detection of renal scars is of paramount importance for optimal clinical management of patients with urinary tract infection (UTI) and vesicoureteral reflux (VUR). The aim of our study was to compare the efficacy of unenhanced magnetic resonance urography (MRU) and Tc-99(m) dimercaptosuccinic acid (Tc-DMSA) scintigraphy to dectect renal scars. METHODS: Unenhanced MRU and Tc-DMSA scintigraphy were performed in 49 children (10 boys, 39 girls; mean age 7.4 ± 4.2 years, range 1-15 years) with documented VUR. MR imaging scans were obtained within 7 days after voiding cystourethrogram (VCUG) and Tc-DMSA scintigraphy. The diagnostic performance of MRU in renal scar detection was calculated relative to that of the Tc-DMSA scan. RESULTS: The renal scar detection rate of Tc-DMSA scintigraphy and unenhanced MRU in kidneys with VUR was 32.4 and 25.9%, respectively. The sensitivity and specificity of MRU in the detection of renal scars was 80 and 82.6% in kidneys with VUR, respectively. There was no statistically significant difference in lesion detection between MRU and Tc-DMSA scintigraphy (P > 0.05). MRU and Tc-DMSA scintigraphy showed good agreement (κ = 0.60). CONCLUSIONS: Unenhanced MRU is a robust technique for the morphologic assessment of the urinary system and detection of renal scars. The lack of radiation and contrast material makes this technique a much safer alternative to scintigraphy in children with VUR, particularly in those who require follow-up scanning and, consequently, considerable radiation exposure.