Patterns of brain atrophy in Parkinson's disease, progressive supranuclear palsy and multiple system atrophy

Abstract

Background and purpose: Quantitative analysis of brain atrophy may be useful in differentiating Parkinson's Disease (PD) from Progressive Supranuclear Palsy (PSP) and parkinsonian variant of Multiple System Atrophy (MSA-P); the aim of this study was to identify the volumetric differences of subcortical structures in patients with PD, PSP and MSA-P using a novel and validated fully-automated whole brain segmentation method.

Methods: Volumetric MRIs were obtained in 72 patients with PD, 32 patients with PSP, 15 patients with MSA-P, and in 46 control subjects. Subcortical volume was measured automatically by FreeSurfer. Multivariate analysis of covariance, adjusted for intracranial volume (ICV), sex and age, was used to explore group differences.

Results: No volumetric differences were found between PD and controls group; otherwise the volumes of the cerebellum, the thalamus, the putamen, the pallidum, the hippocampus, and the brainstem were significantly reduced in PSP and MSA-P compared to patients with PD and control subjects. PSP and MSA-P patients only differed in thalamus volume which was smaller in PSP group (p < 0.001). Moreover, patients with PSP and MSA-P showed a ventricular system (including lateral, third and fourth ventricles) larger than that detected in PD and controls (p < 0.001).

Conclusions: Volumetric data obtained with automated segmentation of cerebral regions show a significant atrophy of different brain structures in parkinsonisms rather than in PD. Our study also demonstrates that the atrophy of the thalamus only occurs in PSP while the enlargement of the whole ventricular system characterizes both PSP and MSA-P.