Neuroimaging advances in Parkinson's disease

Purpose of review Neuroimaging in Parkinson's disease is an evolving field, providing in-vivo insights into the structural and biochemical changes of the condition, although its diagnosis remains clinical. Here, we aim to summarize the most relevant recent advances in neuroimaging in Parkinson's disease to assess the underlying disease process, identify a biomarker of disease progression and guide or monitor therapeutic interventions. Recent findings The clinical applications of imaging technology increasingly allow to quantify pigments (iron, neuromelanin) on MRI, proteins (tau), cell markers (phosphodiesterases, microglia) and neurotransmitter receptors (dopamine, serotonin, noradrenalin, cholin) via PET protocols, activity maps by resting-state and task-dependent functional MRI, as well as microstructural changes (free water) through diffusion-based assessments. Their application provides increasing insight on the temporal and spatial dynamics of dopaminergic and other neurotransmitter systems as well as anatomical structures and circuits in Parkinson's disease. An expanding list of PET tracers increases the yield of functional studies. Summary This review summarizes the most recent, relevant advances in neuroimaging technology in Parkinson's disease. In particular, the combination of different imaging techniques seems promising to maximize the scope of future work, which should, among others, aim at identifying the best imaging marker of disease progression.