A duplex kidney, also called a duplicated collecting system, is a congenital anomaly in which a kidney has two separate renal pelves and ureters instead of the usual single system. This is one of the most common congenital urinary tract variations, occurring in approximately 1 percent of the population. On ultrasound, a duplex kidney may appear larger than normal and may show two distinct central echogenic areas separated by a bridge of renal parenchyma. Duplex kidneys are important to recognize because they can be associated with conditions like ureterocele, vesicoureteral reflux, and ectopic ureter insertion, particularly involving the upper pole moiety, which can lead to obstruction or recurrent urinary tract infections.
Sonography Term