PET Imaging of Neuro-Inflammation with Tracers Targeting the Translocator Protein (TSPO), a Systematic Review: From Bench to Bedside

Parkinson's disease is the second most common neurodegenerative disorder, affecting 2-3% of the population of patients >65 years. Although the standard diagnosis of PD is clinical, neuroimaging plays a key role in the evaluation of patients who present symptoms related to neurodegenerative disorders. MRI, DAT-SPECT, and PET with [F-18]-FDG are routinely used in the diagnosis and focus on the investigation of morphological changes, nigrostriatal degeneration or shifts in glucose metabolism in patients with parkinsonian syndromes. The aim of this study is to review the current PET radiotracers targeting TSPO, a transmembrane protein that is overexpressed by microglia in another pathophysiological process associated with neurodegenerative disorders known as neuroinflammation. To the best of our knowledge, neuroinflammation is present not only in PD but in many other neurodegenerative disorders, including AD, DLB, and MSA, as well as atypical parkinsonian syndromes. Therefore, in this study, specific patterns of microglial activation in PD and the differences in distribution volumes of these radiotracers in patients with PD as compared to other neurodegenerative disorders are reviewed.

Automated summary

Parkinson's disease (PD) is the second most common neurodegenerative disorder, affecting 2-3% of individuals over the age of 65. Neuroimaging techniques such as MRI, DAT-SPECT, and PET are used in the diagnosis of neurodegenerative disorders and focus on identifying morphological changes, nigrostriatal degeneration, and alterations in glucose metabolism in patients with parkinsonian syndromes. This study reviews the use of PET radiotracers targeting TSPO to assess neuroinflammation in PD and other neurodegenerative disorders.