There is accumulating evidence suggesting that inflammatory processes, through microglial activation, would play a key role in brain injury and degeneration. It is considered that microglial activation would be part of self-propelling cycle of neuroinflammation that fuels Neurologic deterioration. It is however hard to evidence microglial activation in vivo: first, the investigators need very high-resolution imaging tools and then, the only ligand available to date, 11C-PK11195, has a low sensitivity and specificity and provided heterogeneous results. 18F-DPA-714 is a new PET ligand which labels microglial cells. The investigators aim to explore the clinical feasibility used PET-CT with 18F-DPA714 to monitor microglial cells activation of brain in several different disease. This study might reveal significant neuroinflammatory process in the brain. The results of this study might provide a new biomarker of disease pathological progression and help as identifying subjects who might most benefit from a specific anti-inflammatory drug.

Inclusion Criteria:

• Age > 18 years
• Positron emission tomography scans were acquired more than twice
• Written informed consent was provided by the patients and their health care proxies -

Exclusion Criteria:

• Contraindication for PET examination

Patients with neurological or psychiatry diseases or known brain lesion