Figure 2e. Renal cysts in a 49-year-old woman with vague abdominal pain. (a) Oblique IVU image shows a medial lower pole mass (arrow) displacing and distorting the renal pelvis and lower calices. (b) High-dose bolus nephrotomogram obtained in a steeply oblique position demonstrates the same mass (arrowheads) to be lucent and largely well defined. However, a thin, smooth rim could not unequivocally be demonstrated overlying the contrast material-filled calices (arrows). (c, d) Anteroposterior selective arteriograms, therefore, were obtained that showed the mass to be avascular except for a few tumor vessels (arrowhead in c) suspected medially. (e) Anteroposterior selective arteriogram with epinephrine reveals marked decrease in blood flow to the kidney and no tumor vascularity, which indicates that the lesion is a simple cyst.