Amyloid PET findings in multiple sclerosis are associated with cognitive decline at 18 months.

Abstract Objective To study the clinical, cognitive, and radiological progression of a cohort of patients with MS, taking into account the amyloid PET with 18F-florbetaben analyses. Methods Twenty-nine patients with MS were assessed with longitudinal structural MRI and a clinical and comprehensive neuropsychological protocol, with a mean interval between assessments of 18 ± 3.31 months. 18F-florbetaben PET was performed at baseline. Uptake was analysed in demyelinating plaques (DWM) and normal-appearing white matter (NAWM). Results were correlated with clinical, cognitive and MRI data. Results Patients with cognitive decline over the follow-up period showed a lower standardised uptake value ratio in NAWM and lower thalamic volume and a higher lesion load in the baseline MRI. Myelin status was correlated with EDSS and cognitive tests mainly evaluating visuospatial function and working memory. Lower uptake in NAWM at baseline was also associated with a growth in white matter lesion volume over time. Conclusions Lower white matter uptake in amyloid PET is associated with cognitive decline and an increase in white matter lesion volume during the follow-up. Our study suggests that 18F-florbetaben may be a useful biomarker in assessing myelin status in MS, understanding MS pathophysiology, and predicting cognitive outcomes.