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PO088 Nigral iron susceptibility in parkinson’s disease: a longitudinal study

Background Iron accumulation plays an important role in neurodegeneration in Parkinson’s disease. Susceptibility weighted imaging (SWI) is a high-resolution MR-based imaging technique for quantifying iron depositions in vivo. We hypothesised that high-pass filtered phase imaging may be a useful monitoring tool for longitudinal clinical characterisation of PD, and we sought to investigate the clinical associations of iron depositions in deep grey matter nuclei. Methods We evaluated forty-two PD subjects and six age and gender matched healthy volunteers (HV) longitudinally with high-pass filtered phase imaging at baseline and after 18 months. Average phase shifts (radians) substantia nigra (SN) were analysed using SPIN software. Longitudinal changes of bilateral radians (Δ radians) were calculated by subtracting baseline values from follow up values. Parametric correlations of regional Δ radians were conducted with Δ UPDRS part III, tremor and bradykinesia- rigidity sub-scores. Results PD patients showed significantly higher radians in the SN (p<0.001) after 18 months, without significant change in HV. Δ SN radians positively correlated with Δ UPDRS-III (p<0.001) and bradykinesia-rigidity subscores (p=0.001). Conclusions High-pass filtered phase imaging offers an interesting monitoring tool to evaluate longitudinal progression of motor severity and could be useful to assess the effect of iron chelation therapies.