URETERAL DUPLICATION AND ITS COMPLICATIONS

Duplication of the ureters is a common anomaly and is frequently encou ntered by radiologists. Duplication may be either complete or incomple te and is often accompanied by various complications. Incomplete dupli cation is most often associated with ureteroureteral reflux or uretero pelvic junction obstruction of the lower pole of the kidney. Complete duplication is most often associated with vesicoureteral reflux, ectop ic ureterocele, or ectopic ureteral insertion, all of which are more c ommon in girls than in boys. Vesicoureteral reflux affects the lower p ole and can be outgrown,as in nonduplicated systems. Ectopic ureteroce le and ectopic: ureteral insertion affect the upper pole. The ectopic ureterocele produces a filling defect of variable size in the bladder; it can be identified with contrast material studies or ultrasound. Ec topic ureters may function poorly, be difficult to detect, and cause e nuresis in girls. A fourth complication, ureteropelvic junction obstru ction, occurs only in the lower pole and is seen in more boys than gir ls. Anatomic variants or anomalies as well as suboptimal imaging techn iques can either simulate or obscure duplication, making diagnosis dif ficult. However, familiarity with the embryology of duplication and an awareness of the potential pitfalls of excretory urography and voidin g cystourethrography will foster an understanding of the varied appear ances and associated complications of both incomplete and complete dup lication.