Figure 10b. Ureteroduodenal fistula. (a) Frontal radiograph obtained after retrograde contrast agent injection of right upper urinary collecting system in a 67-year-old man shows contrast agent within the duodenum (arrows) from an unsuspected fistula. Note wire (black arrowheads) and small amount of retained contrast agent (white arrowhead) in the collecting system. (b) Contrast-enhanced CT scan performed after a shows site of contact (white arrowhead) between duodenum and right ureter. The fistula likely resulted from injury during previous aortofemoral bypass surgery. Note vascular graft (black arrowhead) and right ureteral stent (arrow).