Objective: We for the first time investigated longitudinal changes of nigral iron load in Parkinson’s disease (PD) measured by Quantitative Susceptibility Mapping (QSM), a highly iron-sensitive MRI method, and its relation to clinical variables.

Background: Iron accumulation in the substantia nigra (SN) is discussed to be an important factor in the pathogenesis of PD. Former studies, based on histological and imaging techniques, showed higher concentrations of iron-ions in the basal ganglia, especially in the substantia nigra of parkinsonian patients compared to healthy controls. However longitudinal data are sparse.

Methods: We included 52 PD-patients (36 male, mean age 62,6±10,7; mean disease duration 4,1 years) and 29 healthy controls (HC) (13 male; mean age 68,1±9,1). All subjects underwent a clinical examination and a 3T MRI scan at baseline and after a follow-up period of approximately 2 years. Nigral iron concentration was determined by QSM. For cross-sectional group comparisons we performed one-way ANOVAs corrected for age and gender, for longitudinal comparisons repeated-measure ANOVAs corrected for age, gender and between-scan-time and for clinical correlations Spearman correlations. To achieve normal distribution QSM values were logarithmised, significances were corrected with Bonferroni correction for multiple comparisons.

Results: QSM values in total SN, SN pars compacta (SNc) and SN pars reticulata (SNr) were significantly higher in PD compared to HC (p<0.001) at baseline and follow-up. There were no significant group differences in longitudinal QSM-change. QSM values in PD tented to increase in SNc and decrease in SNr, in HC they tended to decrease in SNc and SNr. There was no significant correlation for QSM change and change in clinical parameters (MDS-UPDRS, FTM-tremor rating scale, Non Motor symptoms questionnaire, MMSE, LED).

Conclusions: We confirmed higher nigral iron load in PD compared to HC. However there was only a not significant trend for stronger shortterm longitudinal increase of iron concentration in SNc in PD compared to HC. This might be due to relatively long baseline disease duration in our PD subjects and suggests nigral iron accumulation as an early factor in the pathogenesis of PD.

References: This abstract has previously been presented at the 4th Congress of the European Academy of Neurology, 16 – 19 June 2018 and at the 15th Annual Meeting of the Austrian Society of Neurology, 21-23 March 2018.

« Back to 2018 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/longitudinal-development-of-nigral-iron-load-in-parkinsons-disease/