Additional Extra-striatal Site of Neurodegeneration in Parkinson's Disease

摘要

Background: Over the past decade, there is an increasing realization that the thalamus is an extra-striatal region of  non-dopaminergic degeneration in Parkinson's Disease (PD). Objective: To search for any changes in the  thalamic shape or volume in PD by non-invasive structural MRI images. Methods: Twenty volunteers with clinically diagnosed PD participated in the study, in addition to 20 age-matched healthy controls. MRI was conducted on a Philips Achieva 1.5  T scanner  equipped with a 6 channel Sense head-coil. A high resolution, three dimensional (3D) SPGR image data set of the whole brain consisting of 170 axial slices, was acquired for segmentation  purposes and as anatomical reference. For thalami shape analysis, we used a recent  method based on spherical harmonics (SPHARM). To assess the significance of group differences between feature vectors, we used a permutation test. Results: No significant differences in volume were detected in the thalami between the PD group and the control one. However significant (p0.03) shape differences were detected between the left versus right thalami in PD, between the left thalami in PD and controls, and between the right thalami in PD and controls. Conclusion: There are significant changes in the shape-but not the volume- of the thalamus in PD patients. Previous pathological studies would suggest that the shape changes detected in our  study represent degeneration in the centromedian- parafasicular (CM-PF) complex, an area known to represent selective non-dopaminergic degeneration in PD. [Egypt J Neurol Psychiat Neurosurg.  2013; 50(3): 221-225]