[Imaging diagnosis of dementia]

The role of neuroimaging in the diagnosis of dementia diseases is overviewed. In the clinical practice, screening imaging examinations such as X-ray CT and MRI of the brain are useful to exclude cerebrovascular disorders, brain tumors, subdural hematomas, and normal pressure hydrocephalus from neurodegenerative disorders. After differentiating those disorders, the regional distribution patterns of atrophy, neuronal injury, or functional impairment detected by morphological MRI, perfusion SPECT, or 18F-FDG PET are useful for the differential diagnosis of neurodegenerative diseases. Cardiac scintigraphy by 123I- MIBG, dopamine transporter imaging, and amyloid imaging give us pathology specific information such as cardiac autonomic dysfunction mainly by Lewy body disease, nigral degeneration with parkinson's syndrome, and amyloid deposition with Alzheimer's disease. Those structural, functional, and pathology specific neuroimaging tools can be used not only for the early diagnosis, but also for tracing disease progression in understanding the relationship between life style diseases and dementia, and developing disease modifying therapies.