Region-Specific Iron Measured by MRI as a Biomarker for Parkinson's Disease.

The identification of sensitive and specific biomarkers for Parkinson's disease (PD) poses an important clinical challenge. A potential biomarker for early diagnosis and disease monitoring of PD is region-specific iron. Iron accumulation in the substantia nigra pars compacta is considered a main characteristic of PD. However, questions remain, such as the relationship between nigral iron and clinical indices of PD (motor impairment or disease duration). Further, previous studies have suggested the influence of iron on other nuclei. Iron quantification using magnetic resonance imaging (MRI) allows for studies of the relationship between regional iron and clinical symptoms in vivo. Thus, in this review we discuss the following topics: the technological development of MRI in measuring brain iron, nigral iron as a potential marker for PD in both clinical and prodromal stages, other influences of regional iron on PD, and clinical translation and future perspectives.