Thalamic microglial activation in ischemic stroke detected in vivo by PET and [C-11]PK11195

Using quantitative PET, the authors studied the binding of [C-11]PK11195, a marker of activated microglia, in the thalamus of patients with chronic mi ddle cerebral artery infarcts. All patients showed increased [C-11]PK11195 binding in the ipsilateral thalamus, indicating the activation of microglia in degenerating projection areas remote from the primary lesion. A persist ent increase in [C-11]PK11195 binding suggests active, long-term thalamic m icrostructural changes after corticothalamic connection damage.