Interlinking brain mapping and Parkinson's disease: MRI analysis, nigrosome 1 and nigrosome 4

Abstract The nigrosome 1 and 4 regions in the substantia nigra can be assessed separately by using high-spatial-resolution susceptibility map-weighted imaging. The nigrosome 1 region is mainly identified below the red nucleus, while the nigrosome 4 region is located at the level of the lower portion of the red nucleus on coronal-reformatted susceptibility map-weighted imaging. Each region exhibits differential involvement according to clinical stages in idiopathic Parkinson's disease, with the nigrosome 1 region involved earlier, followed by the nigrosome 4 region. Such observations may be supported by coregistered high-spatial-resolution neuromelanin-sensitive imaging and the relationship with the extent of abnormality of dopamine transporter activity. From our results, we suggest that high-spatial-resolution susceptibility map-weighted imaging may serve not only as a diagnostic tool but also as an imaging biomarker for disease severity in idiopathic Parkinson's disease.