The Effect of Iron Accumulation in the Basal Ganglia on the Dysfunction of the Extrapyramidal System in Parkinson’s Disease

Abstract

Parkinson’s disease (PD) is a chronic, steadily progressing disease of the central nervous system (CNS) that belongs to the group of synucleinopathies, which causes significant damage to the health of the elderly and leads to disability in the process of progression. Diffusion-tensor MRI and the susceptibility-weighted imaging (SWI) protocol are modern non-invasive neuroimaging techniques that, when used together with patients with PD, can not only assess the distribution and pathological deposition of iron in the basal ganglia, but also its likely effect on the dysfunction of extrapyramidal system structures. Goal. To determine the quantitative content of iron in the basal ganglia in patients with stage II and III (H/Y) Parkinson ’s disease and evaluate its effect on the dysfunction of the components of the extrapyramidal system. Material and methods . We examined 67patients with PD with II (n = 32) andIII (n = 35) Hoehn/Yahr (H/Y) stages. To everyone was performed a brain scan on a Siemens TrioTim high-field MRI scanner (3T) using the pulse sequence SWI and diffusion-tensor MRI. A quantitative assessment of the degree of iron deposition was carried out using SPIN software in regions of interest (ROIs) on both sides: the dentate nucleus (DN), the substantia nigra (SN), the red nucleus (RN), the putamen (PUT), the globus pallidusm (GP), the head of the caudate nucleus (CN). Also, in the projection of ROIs, the fractional anisotropy (FA) values was calculated. Results. Significant (p <0,05) lower FA values were found in left GP and right RN in patients with stage III (H/Y) in comparison with patients with stage II (H/Y). In patients with stage II (H/Y), significant positive correlations were found between the FA values in the left PUT and the hypointensity of SN, GP, RN (all on both sides) and right CN. The FA value in the right PUT correlated with hypointensity of the left SN. The FA value in the left RN had correlations with the hypointensity of the SN, GP (all on both sides), the right RN, the left PUT, and the right CN. In patients with stage III (H/Y), the only reliable positive correlations were found between the FA values and the hypointensity of the ROIs: left CN and left PUT, right PUT and left CN, left SN and right CN, respectively. SWI hypointensity of the left RN, the right PUT, the left CN, and the right GP correlated positively with the FA value in the right SN. The decrease FA value in the left internal GP correlated with the hypointensity of the right DN and right RN. Conclusion. The deposition of iron in the basal ganglia in PD makes a significant contribution to the progression of the disease and affects the formation of most motor manifestations in this category of patients. A dynamic non-invasive assessment of the degree of iron accumulation in the components of the extrapyramidal system will more closely monitor the course of the neurodegenerative process and form observation groups for the risk of PD complications.