Abstract:Objective: To detect iron content in deep grey matter nucleus of brain by susceptibility weighted imaging (SWI) and to assess the correlation between iron deposition and motor symptoms of Parkinson's disease (PD). Methods: This study enrolled 35 PD patients and 41 age-and sex-matched healthy controls who completed SWI examination on 3 T MRI. The phase value of each nucleus was measured in the phase images. The clinical data such as Hoehn-Yahr stage, scores of the Unified Parkinson's Disease Rating Scale (UPDRS) partⅠ, Ⅱ, Ⅲ and total score were collected. According to the Hoehn-Yahr classification, the PD group was divided into the early group (≤2 grade) and the mid-late group (>2 grade), and in the early group (Hoehn-Yahr classification≤1.5 grade) was divided into the ipsilateral and contralateral groups according to the asymmetry of their motor symptoms, and the distribution of iron content. The differences of phase value of each nucleus in each group were compared, and the correlation between phase value and iron content, UPDRS score and so on were analyzed. Results: The phase value of each nucleus in the control group had a negative linear correlation with the iron content of normal human brain reported in the literature (r=-0.809, P=0.028). The phase value of substantia nigra pars compactac (SNc) in the PD group was significantly lower than that of the control group (P=0.011), and the phase value of SNc portion in the mid-late PD group was significantly lower than that of the control group (P=0.014). The SNc phase value of the ipsilateral and contralateral group in the early PD group was significantly different (P<0.001), and the SNc phase value of the contralateral group was significantly lower than that of the control group (P=0.032). The phase value of SNc of PD group showed a negatively linear correlation with UPDRS-Ⅱscore (r=-0.364, P=0.032). Conclusion: The iron content of SNc gradually increase during the progression of PD, mainly in the middle and late stages. The asymmetric distribution of SNc iron deposits in early PD is related to the asymmetry of motor symptoms. Iron deposition in SNc of PD patients is positively linear correlated with motor symptoms, indicating that it may function as a biomarker for monitoring PD progression.
