Abstract 1973

Introduction: The renal scintigraphy with Tc99m-meso-2,3-dimercaptosuccinic acid (Tc99m-DMSA) is important in the evaluation of the morphology and quantification of the functioning renal mass, specially for the contribution of each kidney to the total renal function.

Objectives: The aim of this study is to evaluate and define normal limits of the absolute renal uptake of Tc99m-DMSA in children with normal renal function and to correlate with age.

Methods: Cohort study with children in follow-up for urinary tract infection, normal renal function and absence of urinary abnormalities after image evaluation (ultrasound and voiding cystourethrography). The relative and absolute renal uptake of Tc99m-DMSA of each kidney were calculated according to the administered dose. Uptake of Tc99m-DMSA was calculated 6 hours after IV injection of 0.05 mCi/kg of Tc99m-DMSA (minimal dose of 0.5 mCi) using an Orbiter Siemens ZLC75 gamma camera. Creatinine clearance was calculated using the Schwartz formula. Correlation between uptake of Tc99m-DMSA with age and creatinine clearance with age was by Pearson correlation. Significance level was set at 0.05.

Results: A total of 21 children were studied (median 51 months; range: 6 to 124), all presented normal Tc99m-DMSA scintigraphy. The absolute renal uptake of Tc99m-DMSA was 22±3% for the right and 23±3% for the left kidney (mean±SD). The renal uptake of Tc99m-DMSA showed no correlation with age (right kidney, r=0.30, p=0.19; left kidney, r=0.43, p=0.06). The creatinine clearance was correlated with age (r=0.50; p=0.02).

Conclusion: The values of the absolute renal uptake of Tc99m-DMSA in children with normal renal function had little variation with age, distinctively to the observed with the creatinine clearance, which exhibited physiologic variation. The authors highlight that the absolute renal uptake of Tc99m-DMSA can be of great value in the evaluation of pediatric patients with renal pathologies, specially in bilateral attempt or single kidney.