Structural Imaging in Parkinson's Disease: New Developments

To review the advances in structural imaging for the diagnosis, prognosis, and treatment of Parkinson's disease (PD) during the last 5 years.

Structural imaging using high-field MRI (≥ 3 T) and new MR sequences sensitive to iron and nigral pigments have achieved to assess in vivo pathological surrogates useful for PD diagnosis (notably decreased nigral neuromelanin and loss of dorsal nigral hyperintensity, increased nigral iron content, diffusivity, and free-water), prodromal diagnosis (decreased neuromelanin signal in the locus coeruleus), and PD progression (with increasing nigral iron content (increasing R2* rate) and nigral damage (increasing free-water)). Additionally, evaluation of atrophy in small monoaminergic nuclei is useful for prognosis, including cholinergic basal forebrain nuclei atrophy for cognitive impairment. New advances in multimodal structural imaging improve diagnosis, prognosis, and prediction of invasive treatment outcome in PD, and may further benefit from machine learning and large scale longitudinal studies to better identify prognostic subtypes.