[The basics of imaging dementia]

Dementia is becoming more common as the population ages. We review the prevalence of different causes of dementia. Alzheimer's disease heads the list, followed by vascular dementia, Lewy body dementia, and frontotemporal lobar degeneration. Although these are distinct entities, their symptoms overlap and they have many comorbid conditions in common. We review the importance of recognizing the early symptoms and signs of dementia and point out the key differences between different types of dementia. We illustrate the fundamental importance of differentiating between reversible and irreversible disease on imaging and of establishing the follow-up of patients with irreversible conditions.