Introduction: Dementia is a clinical diagnosis based on deficits of intellectual function, usually memory. Primarily neurodegenerative diseases are characterized by progressive neuronal damages and its synapsis. Early-onset Alzheimer disease 18 occurs in someone younger than 65. FDG-PET/CTis a quantitative tomographic technique also calleda biomarker of neuronal activity.

Case outline: A female of 54, mother, 12 years of education, an accountant, was sent to FDG-PET/CT brain scan because of loss of memory, social withdrawal, apathy, behavior changes, troubles with paying bills, speaking difficulties with no structural imaging abnormalities. PET scan reviled glucose hypometabolism in parietal lobes, left posterior cingulum, parietotemporal regions, the left parietooccipital region, left insula and temporal lobes. A male of 43, father, army corporal, 12 years of education, was sent to metabolic hybrid imaging because suspected dementia. He expressed progressive behavior decline, in a year time. The patient wasn't cooperative, could not concentrate and confabulated a lot. Forgetfulness, decline in voluntary dynamics and apathy dominated the clinical presentation. Structural imaging showed supratentorial, right precentral gyri solitary lesion and cortical bilateral hypocampal atrophy. FDG scan reviled distinctively diminished glucose metabolism posteriorly in parietal and temporal lobes, both posterior cingulum. SPM analysis confirmed the visually observed pattern of hypometabolism in both patients.

Conclusion: Depression is an important consideration in the differential diagnosis of AD. Early detection of AD through molecular imaging techniques will assist the choice of medications to slow the progression of the disease and optimize patient care.