Figure 9. Left middle cerebral artery infarct. (A) Regional cerebral blood flow map from computed tomography perfusion shows a large perfusion defect in the left frontal and temporal lobes, evidenced by a lack of color display. (B) Regional cerebral blood volume map demonstrates a penumbra of decreased perfusion (indicated with arrows around blue areas) surrounding the defect (purple), indicating potentially reversible ischemia about the perfusion defect.