COMPLETE DUPLICATION OF THE URETER WITH URETEROPELVIC JUNCTION OBSTRUCTION OF THE LOWER POLE OF THE KIDNEY - IMAGING FINDINGS

OBJECTIVE. The purpose of our study was to identify the radiographic s igns that aid in the diagnosis of obstruction of the ureteropelvic jun ction of the lower pole (or moiety) of the kidney in children with com plete duplication of the ureter and to describe the imaging appearance of this unusual cause of tower-pole hydronephrosis. MATERIALS AND MET HODS, We reviewed the medical records and imaging studies of 16 childr en (11 boys and five girls) with complete ureteral duplication and ure teropelvic junction obstruction of the lower pole of the kidney over a 5-year period. Standard criteria for determining urinary tract obstru ction were used. RESULTS. Sonograms showed a lower-pole abnormality (h ydronephrosis or cystic mass) in all 15 children who underwent sonogra phy, Voiding cystourethrography, performed for all children, showed ve sicoureteral reflux into the lower pole in addition to ureteropelvic j unction obstruction in eight children (seven boys and one girl), For t he other eight, the diagnosis of lower-pole ureteropelvic junction obs truction was made by excretory urography, at times complemented with d iuretic renography or retrograde ureterography. CONCLUSION. Ureteropel vic junction obstruction of the lower pole of the kidney in children w ith complete duplication of the ureter should be a diagnostic consider ation when there is dilatation of the lower moiety. Imaging changes pa rallel those of ureteropelvic junction obstruction in a nonduplicated system, This anomaly, unlike others seen in duplication, appears to be more common in boys than in girls.