Comparison of iron deposition in subcortical structures of brains with Parkinsonian syndromes: A post-mortem 7.0-tesla magnetic resonance study

Abstract

It is not known whether iron (Fe) accumulation is a secondary event in the cascade of the neuronal degeneration rather than the primary cause in different Parkinsonian diseases. The purpose of the present post-mortem study is to evaluate and compare the Fe content in brains of different parkinsonian syndromes with normal control brains. Twenty-six normal brains were compared to 7 with idiopathic Parkinson’s disease (PD), 18 with progressive supranuclear palsy (PSP), 18 with Lewy body dementia (LBD), 6 with corticobasal degeneration (CBD) and 5 with multiple system atrophy (MSA). The hippocampus and 11 subcortical structures were submitted to a 7.0-tesla magnetic resonance imaging (MRI). T2 and T2* sequences were performed: the degree of T2* hypo-intensity, representing the degree of Fe content in the different brain regions, was determined semi-quantitatively. No significant differences in Fe content were observed in all examined structures between normal brains and those with PD, PSP, LBD and CBD. In MSA there was a selective hypo-intensity on T2* sequence in the putamen, reflecting Fe increase, with on the other hand a significant Fe decrease at the level of the dentate nucleus of the cerebellum. The present post-mortem MRI study confirms that the increased hypo-intensity in the putamen is a diagnostic hallmark of MSA, but that also the low Fe content at the level of the dentate nucleus has also to be considered as a valuable indicator of this disease.