Neuroimaging of Diseases Causing Dementia

Neuroimaging provides a window on the biological events underlying dementia. Amyloid PET is positive in Alzheimer disease (AD) and some cases of diffuse Lewy body disease, but negative in the frontotemporal dementias (FTDs). Tau PET using the current tracers shows the greatest signal in AD and a lesser signal in FTD. Quantifying volume loss with MRI and measuring metabolism with fluorodeoxyglucose PET helps separate different causes of dementia and follow their progression. Brain inflammation can be assessed with PET. Some of these techniques, still investigational, are likely to find their clinical niche in the near future.