Figure 4: Patient with a right MCA occlusion and prominent ACA collaterals. Panel A shows the conventional dynamic CTA without color-coding. Panel B shows a color-coded dynamic CTA (ACA = Red, MCA = Blue). The right MCA is occluded, which is evident from the absence of blue branches in the right hemisphere. The ACA supplies collateral fl ow to the right MCA territory via leptomeningeal vessels, which is evidenced by the red branches over the right cerebral convexity