Redistribution of renal blood flow caused by contrast media

Rerouting of blood from the renal cortex to the renal medulla (Trueta shunting), observed in 5 cases, may occur in normal kidneys during renal angiography. The temporary nature of this artifact may be proved by performing an abdominal aortogram with the catheter tip inserted farther away from the renal arteries. The exact mechanism of this phenomenon is unknown; it may also occur with various renovascular disorders.