Dual Phase Amyloid PET in Newly Diagnosed Multiple Sclerosis: Exploring Its Potential as a Biomarker of Myelination and Neurodegeneration

Background: Amyloid positron emission tomography (PET) has been proposed as a tool to monitor myelination in multiple sclerosis (MS). We present the first study to include both early and standard phases of amyloid PET in patients with newly diagnosed MS. Methods: Prospective study including patients with newly diagnosed MS (Jan 2023-Feb 2024). Clinical evaluation includes neurological, disability (EDSS) and neuropsychological assessment. Brain MRI, early 18F-florbetaben (FBB) PET (eFBB; 0–5’, 0-10’ p.i.), and standard FBB PET (sFBB; 90’ p.i.) were acquired. Normal-appearing white matter (NAWM) and damaged (DWM) in MRI were segmented and co-registered with PET images. Results are presented as standardized uptake values (SUV), ratio using cerebellum as the reference region (SUVR) and percentage of change between DWM and NAWM. Results: Twenty patients were included (35.05±10.72 years; 75% women). We found, both “eFBB and sFBB adquistions” a lower mean SUVRmax and SUVRmean and higher mean SUVRmin in DWM compared to NAWM (p<0.001) in all patients. SUV parameters in both DWM and NAWM from eFBB and sFBB PET correlated with the number of relapses and EDSS (r = –0.454 and r = –0.446, respectively; p < 0.05). Additionally, SUVR values in DWM during eFBB correlated with cognitive impairment (SDMT; r = –0.516, p < 0.01), fatigue (MFIS–5; r = –0.450, p < 0.05), and quality of life (EQ-5D; r = –0.490, p < 0.05). Conclusion: Quantitative analysis of dual phase FBB PET demonstrates differential uptake between DWM and NAWM, probably associated with demyelination and neurodegeneration. These preliminary findings suggest that amyloid PET may have predictive value for disease activity and progression, supporting its potential as a biomarker in MS.