RESUMO
PURPOSE: We evaluated whether increased split renal function ratio (%) on the renal scan with Tc-99m diethylenetriamine pinta-acetic acid (DTPA) represent elevated renal function in the obstructed kidney. MATERIALS AND METHODS: From 1994 to 1995, we evaluated 36 patients with unilateral hydronephrosis due to ureteropelvic junction (UPJ) obstruction and split renal function ratios of the affected kidneys were calculated using Tc-99m DTPA renal scan. RESULTS: Of the 36 patients, 7 patients showed that split renal function ratios of the affected kidneys were all over 52%. To assess the significance of the split renal function ratio on the Tc-99m DTPA renal scan, we performed Tc-99m mercaptoacetyltriglycine (MAG3) renal scan with the time interval of 3 days and calculated the split renal function ratios of the affected kidneys on the MAG3 renal scan in all 7 patients. The split renal function ratios of the affected kidneys on the MAG3 renal scan were also higher than those of the normal kidney. And the split renal function ratios of the affected kidneys on the MAG3 renal scan were well correlated with those of DTPA renal scan (r=0.83). CONCLUSIONS: Our results suggest that the increased split renal function ratio in affected kidney due to UPJ obstruction is not an artifact of the DTPA renogram.