Nowadays, the role of magnetic resonance imaging in dementia diagnosis such as Alzheimer, Vascular dementia, Dementia Lewi bodies and Pakinson disease…. MRI may support the diagnosis of specific neurodegenerative disorders and sometimes MRI are necessary to confirm the diagnosis. It is a challenge for neuroimaging to contribute to the early diagnosis of neurodegenerative diseases such as Alzheimer's disease. Early diagnosis includes recognition of pre-dementia conditions, such as mild cognitive impairment (MCI). In addition, early diagnosis allows early treatment using currently available therapies or new therapies in the future. Neuroimaging may also be used to assess disease progression and is adopted in current trials investigating MCI and AD. The coronal image shows the hippocampus, the main structure involved in many forms of dementia