Quantitative multiparametric MRI describes neuromelanin-linked pathogenesis in the AAV-hTyr rat model of Parkinson’s disease

Imaging of the neuromelanin (NM) has recently developed as a relevant biomarker of Parkinson’s disease (PD). Here, we present a longitudinal, quantitative, multiparametric study on the AAV-hTyr rat model of PD with NM accumulation in the right substantia nigra. Our protocol allowed to obtain NM-sensitive image, as well as R1, R2* and qMT in a single session. Longitudinal acquisition on AAV-hTyr rats showed inverted U-shaped curve of NM-MRI contrast-to-noise ratio, suggesting NM accumulation followed by neurodegeneration. R1, R2*, MPF and motor symptoms support this hypothesis. Our work may help to understand the pathogenesis of this PD model and identify biomarkers.