Iron is an important element for brain oxygen transport, myelination, DNA synthesis and neurotransmission. However, excessive iron can generate reactive oxygen species and contribute neurotoxicity. Although brain iron deposition is the natural process with normal aging, excessive iron accumulation is also observed in various neurological disorders such as neurodegeneration with brain iron accumulation, Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, Friedreich ataxia, and others. Magnetic resonance image (MRI) is a useful method for detecting iron deposits in the brain. It can be a powerful tool for diagnosis and monitoring, while furthering our understanding of the role of iron in the pathophysiology of a disease. In this review, we will introduce the mechanism of iron toxicity and the basics of several iron-related MRI techniques. Also, we will summarize the previous results concerning the clinical application of such MR imagings in various neurological disorders.

Restless legs syndrome (RLS) is a sensorimotor neurological disorder in which the primary symptom is a compellingurge to move the legs, accompanied by unpleasant and disturbing sensations in the legs. Although pathophysiologicmechanism of RLS is still unclear, several evidences suggest that RLS is related to dysfunction in central nervous systeminvolving brain and spinal cord. L-DOPA, as the precursor of dopamine, as well as dopamine agonists, plays an essentialrole in the treatment of RLS leading to the assumption of a key role of dopamine function in the pathophysiology ofRLS. Patients with RLS have lower levels of dopamine in the substantia nigra and respond to iron administration. Iron,as a cofactor in dopamine production, plays a central role in the etiology of RLS. Functional neuroimaging studies usingPET and SPECT support a central striatal D2 receptor abnormality in the pathophysiology of RLS. Functional MRIsuggested a central generator of periodic limb movements during sleep (PLMs) in RLS. However, to date, we have nodirect evidence of pathogenic mechanisms of RLS.