Fig. 10

A 76-year-old female with symptomatic left carotid stenosis (70% by North American Symptomatic Carotid Endarterectomy Trial criteria) who presented with right homonymous hemianopia compatible with a left posterior cerebral artery stroke. Arterial spin labeling demonstrates hypoperfusion throughout the left cerebral hemisphere (a) and CTA demonstrates a fetal left posterior cerebral artery supplied by the left internal carotid artery (b). Florbetaben PET/CT demonstrates no to sparse amyloid plaque (c). Flortaucipir PET/CT prior to the event demonstrates no areas of cortical tau retention (d). Flortaucipir PET/CT following the event (e) demonstrates focal tau retention in the left posterior cerebral artery territory (arrows), likely as a response to cerebral ischemia