Metabolic Positron Emission Tomography Response to Gamma Knife of the Ventral Intermediate Nucleus in Essential Tremor

International audienceBackground: To understand the substrate of response and non-response, and identify potential biomarkers for selection and follow-up of patients with essential tremor (ET) treated by Gamma-Knife of the Ventrointermedius nucleus (GKVIM).Objective: This observational study aims to characterize PET changes in metabolism of glucose and metabolic connectivity in patients with ET treated by GKVIM. Methods: Forty-two patients with right ET were referred to 18F-FDG PET imaging before, and after left GKVIM. Statistical Parametric Mapping-T score maps comparisons were performedbetween pre- and post-GKVIM groups, and between clinical responders and non-responders. Metabolic connectivity was evaluated by interregional correlation analysis method.Results: After GKVIM, patients with ET exhibited a decrease of the left thalamic metabolism, associated with remote metabolic decreases in the right cerebellum, left temporal gyri, and bilateral frontal gyri (p<0.05 with family-wise error correction). Non-responders (n=7) additionally showed after GKVIM a metabolic decrease in the right temporo-occipital area (p