LAUSR

Brain and more specifically cerebellar atrophy is a major radiological finding in both Paraneoplastic Cerebellar Degeneration (PCD) with anti-Yo antibodies and Spinocerebellar Ataxia type 1 (SCA1).We sought to analyze the different brain volumetric patterns of cerebellar atrophy in these diseases. We performed a retrospective multicentric study (Paris, Lyon, Barcelona reference centres) with either anti-Yo PCD (n=16) or SCA1 (n=17) and 30 healthy subjects paired by age. We used VolBrain and CERES algorithms to obtain the brain and cerebellum segmentation, respectively as well as the cortical thickness. We used a Sparse Canonical Correlation Analysis (SCCAN) and Voxel Brain Morphometry (VBM) with family wise error correction to analyze volumetric differences between the different conditions. SCA patients were younger than PCD patients (p<0.05, ANOVA). In univariate analysis, most of the atrophic regions (p<0.05) were common between PCD and SCA1 compared to controls. Isolated cortical thickness and grey matter analysis showed predominant atrophy in PCD patients. Multivariate analysis using SCCAN and VBM confirmed these results. We identified a particular atrophy pattern in PCD patients involving lobules III to VII. We observed a more diffuse atrophy distribution in SCA1 patients and a lower cortical atrophy in PCD patients. We described the specific pattern of topographic cerebellar atrophy in PCD and SCA1 patients. The cerebellar atrophy in PCD is mainly localized in the neocerebellum.