Microstructural alterations of cerebellar peduncles in multiple sclerosis: a diffusion tensor imaging study.

Background and purpose: Ataxia, tremors, dysarthria, and sometimes impaired cognition are the signs of cerebellum involvement in multiple sclerosis (MS). These symptoms affect up to 80% of patients and are usually hard to treat. To find the underlying involvement of the cerebellum in MS, we assessed the microstructural alterations with DTI in the cerebellar peduncles of the affected subjects.

Materials and methods: We included 58 relapsing-remitting MS patients and 27 healthy controls. Patients were divided into 18 patients of relapsing-remitting MS with cerebellar impairment (RRMSc) and 40 without cerebellar impairment (RRMSnc). Using Diffusion Tensor Imaging (DTI), we calculated fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) metrics in all subjects. We also checked if there were associations between DTI metrics and clinical cerebellar measures (i.e., tremor severity and the scale for the assessment and rating of ataxia).

Results: ANOVA and post-hoc results showed significant differences in DTI metrics between RRMSc and HC and between RRMSnc and HC subjects. Inferior peduncle RD remained the only metric with a significant difference across all pairwise comparisons. The general linear model assessing the effects of the three study groups on the association between DTI metrics and clinical cerebellar measures yielded no significant result.

Conclusions: Our study showed that DTI can mainly reveal significant differences between different MS groups and HCs. Our results imply the role of cerebellar peduncles in the pathophysiology of MS and that this role does not necessarily reflect the severity of cerebellar signs of the patients.