Effect of Corticosteroids on Inflammation at the Edge of Acute Multiple Sclerosis Plaques

* INCLUSION CRITERIA: * Multiple sclerosis, as defined by the 2017 Revised McDonald Criteria; * Age 18 or older; * Ability to provide informed consent; * Able to participate in study procedures and provide high-quality clinical research and imaging data, based on limited artifacts on prior MRI scans and, when possible to determine; * Presence of a gadolinium enhancing lesion on the screening (3T or 7T) brain MRI that demonstrates either centripetal/rim enhancement or a phase rim, or both; * Simultaneously participates in another screening or natural history protocol within the NINDS Neuroimmunology Clinic at the time of study entry. * Willing to use birth control if able to conceive a child EXCLUSION CRITERIA: * Medical contraindications for MRI (e.g., any non-organic implant or other device such as a cardiac pacemaker or infusion pump or other metallic implants, objects, or body piercings that are not MRI-compatible or cannot be removed); * Psychological contraindications for MRI (e.g., claustrophobia), to be assessed at the time the medical history is collected; * Treatment with systemic steroids in previous 30 days (non-systemic administration of steroids, such as topical or local injection, is acceptable); * Experiencing new neurological symptoms, with onset in previous 2 weeks, attributable to MS relapse; * Pregnancy or current breastfeeding; * Screening labs, only if required per current NIH Clinical Center guidelines for kidney-function screening before gadolinium-based MRI contrast, demonstrating estimated glomerular filtration rate \<60 mL/min; * Known hypersensitivity to gadolinium-based contrast agents; * Medical contraindications to corticosteroid administration (e.g., diabetes, gastric ulcer)