Normally each kidney receives one renal artery. Accessory renal arteries can also exist with 10-15% being bilaterally and up to 4 renal arteries bellow 1% of all cases of extrarenal arteries. Accessory arteries usually arise from the aorta or iliac arteries anywhere from the level of T11 to the level of L4 in the images above showed at L3 - best demonstrated in the Volume-rendered images and the coronal MIP images.

In 40% of all cases, the accessory lower pole segment vessel is found and observed to compress the ureter, causing pelviureteric junction obstruction.