Iron metabolism and its detection through MRI in parkinsonian disorders: a systematic review

Iron deposition in the brain normally increase with age, but its accumulation in certain regions is observed in a number of neurodegenerative diseases including Parkinson's disease (PD) and other parkinsonisms. Whether iron overload leads to dopaminergic neuronal death in the SN of PD patients or is instead simply a by-product of the neurodegenerative progression is still yet to be ascertained. Magnetic resonance imaging (MRI) is a non-invasive method to assess brain iron content in PD patients. In PD, accurate radiologic visualization of basal ganglia is required. Deep gray matter nuclei are well presented in T2- and T2*-weighted images. T2*-weighted gradient-echo (GRE) is widely used to assess calcifications and also for iron detection. On the other hand, new methods specifically designed for detecting iron-induced susceptibility differences can be further improved by sequences like susceptibility-weighted imaging (SWI). In the present review, we aim to summarize the available data on brain iron deposition in PD.