Imaging Morphologic Substrates and Molecular Changes for Differential Diagnosis of Vascular Dementia

Abstract

The differential diagnosis of dementias is based on symptoms of cognitive and memory impairment and is supported by results of neuropsychological tests and of imaging. Whereas computed tomography and magnetic resonance imaging are able to detect morphologic substrates of vascular dementias as multi-infarct syndroms, large vessel and critically located strokes, small vessel disease and hemorrhages, these modalities cannot determine molecular causes and functional consequences of the underlying pathologies. Positron emission tomography allows imaging of the localized and/or diffuse metabolic and molecular disturbances responsible for cognitive impairment and dementia, and is effective in differentiating vascular from degenerative dementia, as Alzheimer's disease. Imaging of neurotransmitters and of pathologically accumulated proteins as well as of inflammation additionally yields insight into disease specific pathophysiology. Despite that the broad clinical application of PET is limited, this technology has a great impact on research in dementia.