Figure 1b. (a) Coronal volume-rendered image at the level of the abdominal aorta shows a normal left renal main artery (black arrows) and vein (white arrows) that have classic anatomic structure. (b) Coronal volume-rendered image slightly posterior to a shows an accessory artery (black arrow) and accessory vein (white arrows) connected to the lower pole of the left kidney and a small renal calculus in the upper pole (arrowhead). (c) Axial MIP image shows small bilateral renal calculi (arrowheads), as well as the classically structured main renal artery (black arrow) and vein (white arrow). (d) Axial volume-rendered image shows the polar artery (solid arrow) and the retroaortic polar vein (open arrows).