¹⁸F-FDG PET imaging in early diagnosis of multiple system atrophy

Objective: To evaluate the feasibility of ¹⁸F-FDG PET/CT imaging in the early diagnosis of multiple system atrophy (MSA) and differentiation from early PD. Methods: Five patients with MSA were included in this study. These patients had a disease duration of less than 2 years, predominantly with cerebellar dysfunction (MSA-C). Ten clinically confirmed PD patients with disease duration less than 3 years were also enrolled. All patients underwent ¹⁸F-FDG PET/CT imaging. To compare the metabolic features of these two diseases, SPM 5 software and t-test were used for image data analysis. The PD related pattern (PDRP) expression was calculated in all patients and the efficacy of the PDRP score in distinguishing early MSA from PD was evaluated. Results: At the t-test level of P=0.01, all the 5 MSA patients displayed cerebellar hypometabolism (t: -13.04 to -3.75) and 3 of them also had decreased metabolism in the putamen (t: -5.14 to -3.21). On the contrary, all PD patients showed cerebellar hypermetabolism (t: 4.16 to 11.72) and normal metabolism in putamen. The PDRP scores in the PD group were significantly higher than those in the MSA group (11.9±4.96 vs -6.25±5.97, t=6.27, P<0.01). Conclusions: Cerebellar hypometabolism is the predominant FDG-PET feature of MSA-C, which may be used to distinguish it from early PD. Striatum may be involved in the early phase of MSA-C, displaying hypometabolism in putamen. The PDRP scores are also helpful in differentiating early phase MSA-C from early PD. (authors)