FIG 1.

A patient presented with right MCA syndrome to an outside hospital, last known healthy >8 hours before arrival. The initial brain CT at the outside institution demonstrated acute ischemic changes in the right temporal lobe and insula with an ASPECTS of 6 (A and B). CT perfusion performed at our hospital reconstructed using both manual (Advantage Workstation; GE Healthcare, not shown) and automated (Viz.ai Intelligent Care Coordination; https://www.viz.ai; C) perfusion software demonstrates a large area of acute ischemia (time-to maximum, >6 seconds of 249 mL), but a minimal core infarct (CBF of <30% of 2 mL). Cerebral angiography prethrombectomy demonstrates partial recanalization of the right M1 segment with some antegrade flow (D). The patient underwent successful thrombectomy of the M1 segment (E). Follow-up MR imaging demonstrates areas of restricted diffusion corresponding to the areas of ASPECTS abnormality on the original CT scan, the “perfusion scotoma” (F and G). rCBF indicates relative CBF; Tmax, time-to-maximum.