Duplicated collecting system

Patient A: Duplicated collecting system IVP

Patient A: Duplicated collecting system on CT

Patient B: Duplicated collecting system on CT

Patient B: Upper pole ureter inserting medially

Two pyelocalyceal systems associated with single or double ureters. The ureters empty separately into the bladder or fuse to form a single ureteral orifice. Can be unilateral or bilateral and occur in 15% of the population, F>M.

During embryogenesis, if a single ureteral bud bifurcates before bifurcation of the ampulla, a duplex kidney results with bifid pelvis or bifid ureter. If two ureteral buds arise from the Wolffian duct, a duplex kidney results with complete ureteral duplication.

Weigert Meyer Rule

Upper Pole

• Ectopic
• Inferomedial insertion
• Ureterocele
• Obstructed
• Incontinence in females may be caused by insertion into vagina

Lower Pole

• Reflux