Nuclear medicine investigations in dementia and parkinsonism

Abstract

The incidence of neurodegenerative brain disorders presenting as dementia or parkinsonism is increasing with population aging. Early and correct diagnosis is essential for the exclusion of po-tentially curable causes, to optimize symptomatic treatment, social care and to select patients for clinical trials. Final diagnosis of most neurodegenerative brain diseases can only be made by histopathological examination of the brain tissue. However, functional nuclear-medicine investigations contribute greatly to the diagnosis in vivo. Changes in regional brain metabolism, neurotransmitter system dysfunction and misfolded protein deposition can be observed. Based on specific changes in regional brain metabolism measured with 18F-FDG PET, we can distingu-ish between Alzheimer’s disease, dementia with Lewy bodies and frontotemporal dementia, and between Parkinson’s disease and other neurodegenerative parkinsonisms. Dopaminergic system imaging (e.g. dopamine transporter scintigraphy, DaTSCAN) enables us to discriminate neurodegenerative parkinsonism from alternative causes. Excessive deposition of amyloid-β, a pathological hallmark of Alzheimer’s disease, can be identified by amyloid PET already in preclinical subjects. Nuclear medicine imaging methods, indications, characteristic findings and limitations of these investigations in neurodegenerative brain disorders are presented in this article.