RESUMO
INTRODUCTION: Cognitive impairment is not uncommon in patients with multiple system atrophy (MSA). This study investigated the cortical metabolic changes of MSA and the cortical structure associated with cognitive impairment. METHODS: The study included probable/definite MSA patients who underwent fluorodeoxyglucose positron emission tomography and cognitive evaluation based on mini-mental status examination (MMSE). Cerebral metabolism of the entire MSA patients (n = 88) was compared with healthy controls (n = 19) by voxel-wise statistical parametric mapping. Eight brain regions of interest (ROIs) were selected accordingly: the dorsolateral prefrontal, medial superior frontal, insular, posterior parietal, precuneus, lateral temporal, medial temporal, and posterior cingulate regions. Using validated population-based norms, MSA patients were divided by MMSE z-scores into MSA with cognitive dysfunction (MSA-D, n = 30) and without cognitive dysfunction (MSA-ND, n = 58). Regional metabolism of the selected ROIs was compared between the MSA-D and MSA-ND groups by logistic regression models. Correlations between the regional metabolism of the selected ROIs and MMSE z-scores were analyzed with a linear regression model. RESULTS: Voxel-wise analysis showed hypometabolism in the frontal, temporal, parietal, and limbic areas in MSA patients than in controls. ROI-based comparisons showed that metabolism in the posterior cingulate (P = 0.006) and medial temporal (P = 0.039) regions was significantly lower in the MSA-D than in the MSA-ND group. The degree of posterior cingulate metabolism correlated significantly with MMSE z-score (P = 0.023). CONCLUSIONS: MSA shows fronto-temporo-parietal cortical involvement. Hypometabolism of the limbic regions is associated with cognitive impairment in MSA.