Fig 2. Enhancement in the right and left basal ganglia after injection of 50 mL iodinated contrast agent before and after carotid revasularization.

A, Before treatment, there is symmetric initial enhancement; however, the peak is later and higher and the washout is delayed on the right side compared with the left. This indicates loss in autoregulation and “pooling” of contrast agent.

B, The findings described in A are resolved 1 day after treatment, indicating reversal of vasodilation. A subtle stenotic effect on the right is indicated by a flatter curve and a lower contrast enhancement peak.