ESTIMATION OF DIFFERENTIAL RENAL-FUNCTION IN CHILDREN WITH A PRENATAL-DIAGNOSIS OF UNILATERAL PELVIC DILATATION

Purpose: We compared the estimation of differential renal function by (99m)technetium (Tc)-dimercapto-succinic acid (DMSA) and Tc-99m-pentet ic acid scintigraphic methods for followup of prenatally diagnosed uni lateral renal pelvic dilatation. Materials and Methods: We retrospecti vely analyzed differential renal function estimations calculated by st atic and dynamic methods in time matched test pairs that were included in the charts of 51 children monitored for prenatally diagnosed unila teral renal pelvic dilatation at our institution in a 5-year period. R esults: There were 96 test pairs with available archived raw data. Usi ng the analytic method of assessment of agreement between the 2 tests, a 95% limit of agreement of +/- 9% was calculated. Of the 96 pairs of tests the results of 94 revealed no significant difference. Subgroup analysis by patient age and operative intervention (13 postoperative p airs) also showed no difference in the results of the 2 tests. Conclus ions: We established the 95% limits of agreement between Tc-99m-DMSA a nd Tc-99m-pentetic acid tests of differential renal function to be +/- 9% discrepancy in 96 test pairs. During followup of prenatally diagno sed unilateral renal pelvic dilatation the assessment of differential renal function can be made by Tc-99m-DMSA static or dynamic diuretic r enography techniques. This interchangeability is consistent at all pat ient ages regardless of operative intervention. Since dynamic diuretic renography provides differential function and drainage data, using Tc -99m-DMSA in this context is unnecessary and subjects patients to an u nnecessary radiation burden.