Multiparametric analysis based on 18F-AV133 PET/MR imaging for clinical application in Parkinson’s disease

The progressive loss of dopaminergic neurons and abnormal iron deposition in the central nervous system (CNS) are key pathogenic mechanisms of Parkinson's disease (PD). This study aimed to explore the relationship between iron deposition in specific CNS regions and striatal dysfunction using 18F-AV133 PET/MR imaging. Based on the Hoehn-Yahr stage, 24 patients with early-stage PD (EPD, stage ≤ 2.5), 17 patients with late-stage PD (LPD, stage ≥ 3), and 30 healthy controls (HCs) were recruited for scale evaluation. The specific uptake ratio (SUR) of striatal subregions was calculated using the occipital cortex as the reference region. Quantitative Susceptibility Mapping (QSM) values of major subcortical nuclei were derived through QSM imaging. Spearman correlation analysis was conducted to assess the relationships between SUR in striatal subregions, QSM values in nuclear groups, and PD clinical symptoms, as well as the correlation between SUR and QSM values. Compared to HC, EPD and LPD patients showed significantly reduced VMAT2 distribution in the bilateral caudate nuclei and anteroposterior putamen, particularly in the contralateral posterior putamen. In PD patients, the SUR of striatal subregions and QSM values of the substantia nigra (SN), globus pallidus (GP), and external segment of the GP (GPe) were significantly correlated with disease duration, H&Y stage, UPDRS III score, and NMSS score. Moreover, SUR of striatal subregions was negatively correlated with QSM values in the SN, GP, internal segment of the GP (GPi), and GPe. Multi-parameter analysis revealed a region-specific correlation between striatal dysfunction and iron deposition in PD, offering new avenues to elucidate the underlying mechanisms of the disease.