[Diagnostic differentiation of dementia diseases by modern imaging procedures]

We present a review on recent neuroimaging techniques, like x-ray computed tomography (XCT), magnetic resonance imaging (MRI), positron emission tomography (PET) and single photon emission tomography (SPECT) in dementia and related diseases. Significant new findings have been obtained using techniques reflecting proton density, regional brain perfusion and brain metabolism. In dementia of the Alzheimer type, for example, temporoparietal and sometimes also frontal reductions in cerebral blood flow and metabolism are characteristic. The infarctions found in multi-infarct dementia are especially well visualized on T2-weighted MRI images. Pick's disease is characterized by brain atrophy and decrease of radiotracer activity in the frontal lobes. In huntington's chorea the metabolic rate on PET scan in the area of the caudate nuclei may be reduced even before signs and symptoms become apparent. Furthermore, neuroimaging provides us with fairly typical finding in Creutzfeld-Jakob's disease, alcoholic dementia, Wilson's disease, hydrocephalus, Parkinson's disease, progressive supranuclear ophthalmoplegia, Fahr's disease, and the olivopontocerebellar ataxias. Neuroimaging techniques, however, have always to be interpreted in conjunction with clinical findings, thus disclosing their full range of information.