High-resolution quantitative imaging of the substantia nigra.

There is a growing interest in identifying neuroimaging-based biomarkers for Parkinson's disease (PD), a progressive neurodegenerative disorder in which the major pathologic substrate is the loss of pigmented dopaminergic neurons in the substantia nigra (SN). Recently, an MRI technique dubbed "neuromelanin-sensitive MRI" (NM-MRI), has been found to provide notable contrast between the SN and surrounding brain tissues with potential applications as biomarker of PD. The contrast in NM-MRI has been associated with magnetization transfer (MT) effects, and thus the goal of this study was to characterize the impact of MT on NM-MRI, and to demonstrate the feasibility of performing quantitative MT (qMT) imaging in human SN. The results of this study demonstrate that high-resolution rapid qMT imaging of the SN can be reliably obtained within reasonable scan times, thereby can be translatable into clinical practice.