Case of the Week: Duplicated Collecting System (VCUG & Ultrasound)

In this radiology lecture, we discuss the imaging appearance of duplicated collecting system and ureterocele, with attention to US and VCUG.

Key points include:

Weigert-Meyer rule: Remember the mnemonic “DUMI.”
With duplex kidneys and complete ureteral Duplication, ureter draining Upper pole inserts ectopically into bladder Medially and Inferiorly to ureter draining lower pole.
Lower pole moiety inserts orthotopically.
Upper pole moiety often ends as an ectopic ureterocele.
Upper pole moiety tends to obstruct, and lower pole moiety is prone to reflux.
Obstructed upper pole moiety causes mass effect with resultant inferior displacement of the lower pole moiety and the “drooping lily” sign.