Exploring Pathology Related to Slowly Expanding Lesions Using Advanced Imaging

Inclusion Criteria: * Signing the informed consent form * MS diagnosis in accordance with McDonald 2017 criteria * Available longitudinal brain MR images (minimum 1 year) * Simultaneous QSM MRI sequence and TSPO-PET * Lesions with iron rim/s Exclusion Criteria: * Patients with other neurodegenerative disease than MS * Patients with other autoimmune disease than MS * Patients with other significant or malignant underlying disease of any other organ system * Patients that are pregnant or breast-feeding * Corticosteroid treatment within 4 weeks of imaging * Patients with significant abnormal findings other than MS in the screening MRI * Patients with claustrophobia, or a history of moderate to severe anxiety disorder or panic attacks (which could potentially lead to preterm termination of the imaging) * Contraindication to PET scan investigations * Exposure to experimental radiation in the past 12 months such that radiodosimetry limits would be exceeded by participating in this study * Intolerance to previous PET scans; i.e. previous hypersensitivity reactions to any PET ligand or imaging agent or failure to participate in and comply with previous PET scans