PET Study of Cerebral Metabolism of 11C-acetoacetate and 18F-FDG in Patients Under Moderate Ketosis

PET Study of Cerebral Metabolism of 11C-acetoacetate and 18F-FDG in Patients Under Moderate Ketosis

Regional brain glucose hypometabolism occurs during aging and may contribute to the onset of aging-related cognitive impairment in humans. Ketones are the main alternative energy substrate to glucose for the brain. Several studies show that brain ketone uptake and metabolism are unaltered in cognitively-normal older persons and in Alzheimer's disease (AD). Nutritional ketosis is reported to have a positive impact on cognitive performances in mild cognitive impairment and AD. Nevertheless, changes in regional brain glucose and ketone uptake in adults are poorly understood during diet-induced experimental ketosis. The investigators hypothesis was that during diet-induced ketosis, brain ketone uptake would be directly correlated with the elevation of blood ketone levels and inversely correlated to brain glucose uptake.

Inclusion Criteria:

• Healthy adults
• No signs of cognitive impairment

Exclusion Criteria:

• Not within the age limits
• Pregnancy or breast feeding
• Incapacity to withstand a supine position for 40 min
• Non lacunar infarction
• Known psychiatric history of schizophrenia, psychotic disorders, major affective disorders (bipolar disorder and major depression <5 years), panic disorder, obsessive compulsive disorders and other conditions that may affect memory
• Epilepsy, brain trauma with loss of consciousness, subarachnoid hemorrhage
• History of alcool and/or substances abuse (excessive alcool consumption ≥10 drinks/weeks)
• Parkinson disease
• Down syndrome
• Inflammatory disease
• Abnormal blood pressure, liver or kidney function, blood count
• Dyslipidemia, hypothyroidism, osteoporosis
• Presence of a metal object in the body