Figure 7: 65-year-old male presented at 5 hours post-ictus with improving right hemiparesis and aphasia. The patient did not receive thrombolytic therapy and was monitored in the intensive care unit with hypertensive therapy. (A) CTA 3D MIP reconstruction shows a left middle cerebral artery (MCA) occlusion (arrow).
(B) CTP shows large CBV/CBF mismatch. The CBF and MTT maps demonstrate a large perfusion abnormality in the left MCA territory (arrows) with less than 50% reduction in CBF. The CBV remains preserved in this region, reflecting potential ischemic territory (“ischemic penumbra”).
(C) Initial DWI image at 24 hours post-ictus reveals a small area of acute infarction in the left MCA territory (arrow). Patient was clinically improving, and hypertensive therapy was discontinued.
(D) Follow-up DWI image 48 hours post-ictus reveals growth of the infarction into the “ischemic penumbra” (arrows) seen on the CBF and MTT maps. In this patient with an acute left MCA occlusion, the “ischemic penumbra” could no longer survive when the perfusion pressure was further reduced during a hypotensive episode following cessation of blood pressure treatment.