Magnetic Resonance Imaging of Iron in Parkinson's Disease

The primary pathology of idiopathic Parkinson's disease (PD) is degeneration of the substantia nigra pars compacta. This leads to a reduction in striatal dopamine, which results in the cardinal symptoms of bradykinesia, tremor and rigidity. Increased iron content is consistently reported post-mortem in the substantia nigra of patients with PD and reactive microglia and its capacity to enhance production of toxic reactive oxygen radicals. This may suggest that iron-related oxidative stress may be an important component of the neurodegenerative process in such patients. Presently the mechanisms involved in the disturbances of iron metabolism in PD remain obscure, but evaluating iron contents in brain of PD may be important. Evaluation of iron contents in brain has been possible only with post-mortem study, but advent of MRI techniques makes it possible to evaluate brain iron deposits in vivo. However, previous studies have been inconsistent with the findings compared with post-mortem investigations. This suggests that improved MRI techniques may be useful for assessing brain iron deposits with greater accuracy. In this mini-review, we discussed investigations for assessing brain iron in PD.