The aim of the research is to analyze whether 18F-FDG PET helps in the diagnosis and therefore in the management of the patient.

Neurocognitive disorder or Mild Cognitive Impairment corresponds to a decline in one or more cognitive functions; compared to the previous level of performance.

Indeed, the prevalence of neurodegenerative pathologies is estimated at more than one million according to Santé Publique France, due to the aging of the population. To be compared with the prevalence of the population suffering from a psychiatric disorder estimated at one in five people, or 13 million French people, in 2021.

With the increase in the prevalence of these two entities and their clinical entanglement, the question arises of the origin of neurocognitive disorders, is it a manifestation of a psychiatric pathology or a neurodegenerative pathology not yet diagnosed.

If this is the case, the patient's prognosis is modified with a pejorative evolution and a loss of autonomy which is to be anticipated. This delay deprives the patient and his family of interventions likely to alleviate behavioral disorders; maintain a level of autonomy compatible with life at home; alleviates the burden and improves the quality of life of caregivers.

Inclusion Criteria:

• Adult patients with cognitive impairment
• Positron emission tomography with flurodeoxyglucose labeled with fluorine 18 carried out in the course of care

Exclusion Criteria:

• Patients objecting to the collection of their data

Patients treated for psychiatric reasons with neurocognitive disorders in the clinic, having consulted or being hospitalized at the psychotherapeutic center of Nancy between 01/01/2021 to 01/01/2024 and having undergone a flurodeoxyglucose positron emission tomography marked with fluorine 18 carried out in the course of care