Diuretic 99m Tc DTPA renography in assessment of renal function and drainage in infants with antenatally detected hydronephrosis Značaj diurezne 99m Tc DTPA scintigrafije u proceni renalne funkcije i drenae kod dece sa prenatalno otkrivenom hidronefrozom

Background/Aim. The controversy over the postnatal management of infants with antenataly detected hy- dronephrosis (ANH) still exists. We presented the results of diuretic 99m Tc diethylenetriamine pentaacetic acid (DTPA) renography in 30 infants with the antenatal diagnosis of uni- lateral renal pelvic dilatation. The aim of this study was to assess the renal function determined by the pattern of drainage and split renal function (SRF) on diuretic renogra- phy and to correlate these findings with anteroposterior pelvic diameter (APD) estimated by ultrasonography. Methods. A total of 30 infants with 60 renal units (RU) (25 boys and 5 girls, median age 6.0 months, range 2-24) pre- sented with unilateral hydronephrosis on ultrasound in the newborn period, underwent DTPA diuretic renal scintigra- phy (F+15 protocol). The median APD evaluated on peri- natal ultrasound was 15 mm (range 5-30). The postnatal as- sociated clinical diagnosis were pelviureteric junction ob- struction (PUJ), simple hydronephrosis, megaureter, vesi- coureteral reflux (VUR) and posterior urethral valves in 11, 10, 6, 2 and 1 infant, respectively. Images and Tmax/2 after diuretic stimulation on the background subtracted reno- graphic curves were used as the criteria for classifying the drainage as good, partial, and poor or no drainage. The SRF was calculated with the integral method. Results. Good drainage was shown in 36/60, partial drainage in 13/60 and poor or no drainage in 11/60 RU. The SRF > 40% was ob- served in 55/60 RU, with no RU showing SRF lower than 23.5%. In infants with severe ANH the obstruction was not excluded in 94.1%. Conclusion. Diuretic renography in an- tenatally detected hydronephrosis should be a useful tool in postnatal follow up, especially in differentiating nonobstruc- tive hydronephrosis from obstructive. It is also importanat to assess and monitor the SRF. Our results suggest that even in the presence of partial or no drainage, SRF may not be significantly impaired.