The role of radiotracer imaging in Parkinson disease
Radiotracer imaging (RTI) of the nigrostriatal dopaminergic system is a widely used but controversial biomarker in Parkinson disease (PD). Here the authors review the concepts of biomarker development and the evidence to support the use of four radiotracers as biomarkers in PD: [18F]fluorodopa PET, (+)-[11C]dihydrotetrabenazine PET, [123I] β-CIT SPECT, and [18F] fluorodeoxyglucose PET. Biomarkers used to study disease biology and facilitate drug discovery and early human trials rely on evidence that they are measuring relevant biologic processes. The four tracers fulfill this criterion, although they do not measure the number or density of dopaminergic neurons. Biomarkers used as diagnostic tests, prognostic tools, or surrogate endpoints must not only have biologic relevance but also a strong linkage to the clinical outcome of interest. No radiotracers fulfill these criteria, and current evidence does not support the use of imaging as a diagnostic tool in clinical practice or as a surrogate endpoint in clinical trials. Mechanistic information added by RTI to clinical trials may be difficult to interpret because of uncertainty about the interaction between the interventions and the tracer.
Duke Scholars
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- Neurology & Neurosurgery
- 3209 Neurosciences
- 3202 Clinical sciences
- 1702 Cognitive Sciences
- 1109 Neurosciences
- 1103 Clinical Sciences
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Neurology & Neurosurgery
- 3209 Neurosciences
- 3202 Clinical sciences
- 1702 Cognitive Sciences
- 1109 Neurosciences
- 1103 Clinical Sciences