Role of Iron Depsoition Patterns as Evaluated by Susceptibility-Weighted Imaging of the Brain in Differentiating Parkinson Disease and the Parkinson-Plus Syndromes (P1.012)

OBJECTIVE: To investigate whether differences in brain iron deposition observed with susceptibility weighted imaging (SWI) can differentiate between Parkinson Disease and the Parkinson-Plus Syndromes.BACKGROUND: Patterns of iron deposition can be evaluated using SWI in patients with Parkinson Disease (PD), Multisystem Atrophy - Parkinsonian Type (MSA-P) and the tau protein-related conditions, Progressive Supranuclear Palsy (PSP) and Corticobasal Degeneration (CBD). Previous studies have suggested differential patterns of iron deposition in the putamen, red nucleus, and substantia nigra in these conditions.DESIGN/METHODS: This was a retrospective, cross-sectional study. Twenty-five, 11, and 10 patients with a clinical diagnosis of PD, MSA-P, and PSP/CBD, respectively, who underwent SWI of the brain were included. Two neuroradiologists produced SWI hypointensity scores based on the background and minimum signal intensity of the caudate nucleus, putamen, globus pallidus, dentate nucleus, red nucleus, and substantia nigra using a five-point scale, with cortical vein intensity=1, cerebrospinal fluid (CSF) intensity=3, and grey matter intensity=5, and intermediate intensities=2 or 4. Statistical analysis was performed with the intraclass correlation (ICC) and Kruskal-Wallis tests with a Bonferroni correction setting the significance threshold at 0.0045.Results: Inter-rater agreement was high for all regions (ICC=0.906). There was a statistically significant difference in scores in the substantia nigra (p=0.002), where PSP/CBD demonstrated the greatest hypointensity (hypointensity score of 2.25) compared with PD and MSA-P (hypointensity scores of 2.82, 2.5, respectively). No significant score differences were seen between any other region (p = 0.034-0.983).CONCLUSION: SWI demonstrates significantly greater mineralization involving the substantia nigra in PSP/CBD, compared with PD and MSA-P. Our data suggests that SWI grading of the substantia nigra may help in differentiating between these conditions. However, our data suggests that other, previously reported differential patterns of iron deposition in the putamen and red nucleus in these conditions may not be reproducible. Disclosure: Dr. Oustwani has nothing to disclose. Dr. Korutz has nothing to disclose. Dr. Lester has nothing to disclose. Dr. Kianirad has nothing to disclose. Dr. Simuni has received personal compensation for activities with Acadia, Abbvie, Allergan, GE Medical, Eli Lilly, Harbor Ibsen, Impax, Lundbeck, Merz, the National Parkinson Foundation, Navidea, Pfizer, TEVA, UCB Pharmaceuticals, and US World Medications Dr. Hijaz has nothing to disclose.