T2-weighted MRI in Parkinson's disease; Substantia nigra pars compacta hypointensity correlates with the clinical scores

Background: Iron accumulation in substantia nigra pars compacta (SNpc) and related intensity and volumetric changes in patients with idiopathic Parkinson's disease (PD) has been reported previously. There are only a few studies evaluating the relation between neuroradiological findings and clinical scores, with contradictory results.
Aims: In this study we aimed to measure the iron-rich brain areas of PD patients and healthy subjects with T2-weighted magnetic resonance imaging (MRI) and to evaluate the relation between the clinical scores of PD patients and these imaging results.
Methods and Materials: T2-weighted MRI findings were studied in 20 patients with PD and 16 healthy controls. The width of SNpc, putamen volume, and the intensity of the basal ganglia were measured. Unified Parkinson's Disease Rating Scale (UPDRS) was used for evaluating the clinical status.
Statistical Analyses: Mann Whitney U test for group comparisons, Wilcoxon sign rank test for comparisons within the patient group, and Spearman's rank correlation coefficient for analyses of correlations were used.
Results: Mean SNpc and dentate nucleus intensities were lower in PD patients than healthy subjects. Mean SNpc width and putamen volumes were lower in patients. Decrease in the intensity of mean SNpc correlated with high UPDRS and rigidity scores.
Conclusion: The results of our study reflect the increase in iron accumulation and oxidative stress in the SNpc in Parkinson's disease. The decrease in the intensity of SNpc correlates with poor clinical scores.

Keywords
Parkinson's disease, magnetic resonance imaging, susbstantia nigra, dentate nucleus, iron