Patients with Covid-19 (Coronavirus disease 19) may experience multiple neurological symptoms .

18F-FDG PET-CT ( Positons EmissionTomography coupled with a Computer Tomography with flurodesoxyglucose labelled with fluor 18), which reflects neuronal glycolytic metabolism, shows early variations in neuronal function.

Moreover the tropism of Covid-19 is essentially pulmonary and the hypothesis of this study is with 18F-FDG PET-CT it's possible to study the relationship between cerebral metabolism and the metabolism of pulmonary lesions following Covid-19 infection.

Patients with Covid-19 may experience multiple neurological symptoms including confusion and headaches (non-specific neurological symptoms), while others develop specific neurological manifestations, including stroke, related to increased bleeding disorders, seizures and signs of encephalitis.

The coronavirus enters the central nervous system through the olfactory bulb, causing olfactory and taste dysfunctions. These symptoms may appear before, during or even after the general symptoms.

Indeed, 18F-FDG PET-CT, which reflects neuronal glycolytic metabolism, shows early variations in neuronal function, even in the absence of morphological changes visualized by MRI (Magnetic Resonance Imaging).

Moreover the tropism of Covid-19 is essentially pulmonary and it is accepted that acute pulmonary lesions are independent risk factors for cerebral hypoxia. Furthermore, the cytokine storm due to COVID-19 and the resulting hyperinflammation state may induce a transient increase in pressure, with endothelial and vascular lesions and increased capillary permeability, and promote pulmonary oedema leading to secondary cerebral damage.

The lung/brain relationship is therefore essential to be studied in pathologies whose main tropism is the lung.

18F-FDG PET has the advantage of being able to explore both cerebral metabolism and the metabolism of COVID-19-related lung lesions.

The hypothesis of this study is that 18F-FDG PET-CT can objectify and characterize central nervous system involvement in Covid-19 infection. It also makes it possible to study the relationship between cerebral metabolism and the metabolism of pulmonary lesions following Covid-19 infection.

Inclusion Criteria:

• Patients aged between 18 and 65 years
• Patient included in the Neurocog-Covid study (i.e. presenting a cognitive disorder that has been objectified on the neuropsychological assessment and having to undergo a cerebral MRI),
• Patient who has received full information about the organization of the research and has given written informed consent (or a third person, independent of the investigator and sponsor, in the case of literacy disability),
• Patient affiliated to or beneficiary of a social security plan

Exclusion Criteria:

• Women of childbearing age who do not have effective contraception.
• Pregnant woman or nursing mother.
• Persons referred to in Articles L. 1121-5, L. 1121-7 and L1121-8 of the Public Health Code.
• Persons deprived of liberty by a judicial or administrative decision, persons undergoing psychiatric care pursuant to articles L. 3212-1 and L. 3213-1
• Contraindication to perform 18F-FDG PET-CT
• Patients with a history of pre-Covid-19 psychiatric or chronic illness
• Persons referred to in Articles L. 1121-5, L. 1121-7 and L1121-8 of the Public Health Code.