Estimation of Differential Renal Function in Children With a Prenatal Diagnosis of Unilateral Pelvic Dilatation

Abstract

We compared the estimation of differential renal function by 99mtechnetium (Tc)-dimercapto-succinic acid (DMSA) and 99mTc-pentetic acid scintigraphic methods for followup of prenatally diagnosed unilateral renal pelvic dilatation. We retrospectively analyzed differential renal function estimations calculated by static and dynamic methods in time matched test pairs that were included in the charts of 51 children monitored for prenatally diagnosed unilateral renal pelvic dilatation at our institution in a 5-year period. There were 96 test pairs with available archived raw data. Using 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 pairs) also showed no difference in the results of the 2 tests. We established the 95% limits of agreement between 99mTc-DMSA and 99mTc-pentetic acid tests of differential renal function to be +/-9% discrepancy in 96 test pairs. During followup of prenatally diagnosed unilateral renal pelvic dilatation the assessment of differential renal function can be made by 99mTc-DMSA static or dynamic diuretic renography techniques. This interchangeability is consistent at all patient ages regardless of operative intervention. Since dynamic diuretic renography provides differential function and drainage data, using 99mTc-DMSA in this context is unnecessary and subjects patients to an unnecessary radiation burden.