Characterizing iron deposition in Parkinson's disease using susceptibility-weighted imaging: an in vivo MR study

Brain-iron deposition has been proposed to play an important role in the pathophysiology of Parkinson's disease (PD). The aim of this study was to evaluate the feasibility of characterizing iron deposition in PD using susceptibility-weighted imaging (SWI), and to investigate the correlation of brain-iron accumulation with the clinical status in patients with PD. Forty patients with PD without dementia and 26 age- and sex-matched healthy controls underwent high-resolution susceptibility-weighted magnetic resonance (MR) imaging. The phase shift values of the bilateral red nucleus (RN), substantia nigra (SN), caudate nucleus (CA), globus pallidus (GP), putamen (PU), thalamus (TH) and frontal white matter (FWM) were examined for their relationship with the clinical status. The iron concentrations of the regions involved in PD, such as the SN, increased more significantly, while those in other regions of interest (ROI) did not elevate significantly. No correlation between the increase of the iron concentrations of the SN and duration of PD was observed. PD, however, was closely associated with the Unified Parkinson's Disease Rating Scale motor score (UPDRS-III). No significant differences were found between earlier-onset and later-onset PD patients in terms of the iron concentrations of the SN. Brain-iron concentration can be evaluated by SWI. Also, the brain-iron concentration in the SN correlated with UPDRS motor score, indicating that iron concentration can function as an in vivo biomarker to objectively evaluate the status of PD.