TSPO and Alzheimer disease: Interestingly, some regions with relative hyperperfusion in our study (e.g., frontal and lateral temporal areas) have been shown to exhibit an increase in translocator protein 18 kDa (TSPO) uptake on PET images, which is used to assess the activation of microglia, in patients with dementia or MCI due to AD, suggesting that neuroinflammation might be another potential mechanism for hyperperfusion [49].