Figure 9:Creation of whole-brain perfused-blood-volume maps from the CTA source images. The unenhanced images (left) are subtracted, after co-registration, from the enhanced CTA-SI (middle), in order to create whole-brain perfused-blood-volume maps (right). The whole-brain perfused-blood-volume maps demonstrate increased conspicuity of the left frontal lobe ischemic region (arrows). Like DWI lesions, CTA-SI and CTA-SI subtraction map lesions, in the absence of early, complete recanalization, are likely to reflect irreversibly infarcted tissue.