Figure 3.

A schematic axial diagram of a kidney to demonstrate the principle of sequential selective occlusion angiography using CEUS (contrast enhanced ultrasound scan). (a) The main renal artery divides into anterior and posterior divisions. The small renal tumour is represented as the green circle circumscribed with dotted red line. The avascular plane or line of Brödel is represented by the dotted line LB. (b) and (c) show the area of ischaemia induced by sequential occlusion of a distal (white) then more proximal division (yellow) of the renal vessel. (d) With occlusion of the anterior division of the renal artery (blue), the area of the tumour is made ischaemic and the segment of the kidney, lying posterior to the line of Brödel is still perfused