Bifid ureters are a not uncommon variant of a partially duplicated collecting system. On rare occasion, one collecting system will terminate in a blind-ending pouch prior to reaching the kidney.  Due to orientation of the blind-ending ureter they rarely fill with contrast and usually remain occult on CT.

These are of little clinical consequence beyond surgical planning for stent placement. However, they may be disconcerting for a urologist or interventionist that unintentionally places a wire in the blind-ending pouch.