Microstructural Alterations of Cerebellar Peduncles in Relapsing Remitting Multiple Sclerosis: a Systematic Review and Meta-Analysis of Diffusion Tensor Imaging Studies

Damage to cerebellar peduncles is common in patients with relapsing-remitting multiple sclerosis (RRMS). This can lead to a diverse range of motor and cognitive disabilities. Here, we aimed to evaluate the quantitative alterations of cerebellar peduncles using diffusion tensor imaging (DTI). After a comprehensive search in Web of Science, PubMed, Embase, and Scopus and a rigorous screening, eligible studies underwent data extraction and risk of bias assessment. Standardized Mean Difference (SMD) with a 95% CI was used as effect size. We compared DTI metrics in the cerebellar peduncle regions (SCP, MCP, ICP) between RRMS patients and healthy controls (HC). Sensitivity analysis employed the leave-one-out method. Contour-enhanced funnel plots and Pustejovsky test were used to evaluate the publication bias. Additionally, subgroup analysis was performed using available variables. In eleven included studies encompassing 623 RRMS patients and 416 HC, RRMS patients exhibited significantly decreased fractional anisotropy (FA) values in the SCP (SMD - 0.26) and MCP (SMD - 1.03), increased mean diffusivity (MD) values in the SCP (SMD 1.46), MCP (SMD 0.48) and ICP (SMD 0.70), elevated radial diffusivity (RD) values in the MCP (SMD 0.85) and ICP (SMD 1.20) compared to HC. The subgroup analysis revealed that individuals with elevated EDSS scores exhibited reduced FA and increased MD in the SCP region. No considerable publication bias was detected. No outliers were detected in the sensitivity analysis. DTI proves promising for identifying microstructural abnormalities in cerebellar peduncles of RRMS patients, with decreased FA and increased RD, and MD values observed.