Additional Study Information: We're testing a new type of MRI scanner that's smaller and portable - like a mobile MRI unit. This makes it easier to provide brain scans to people who have difficulty traveling to hospitals or live far from medical centers. We'll be studying people with multiple sclerosis (MS) and similar brain conditions. Our goal is to learn how well this portable scanner can measure brain changes and how these changes relate to memory and thinking abilities. By validating this technology, we hope to make MRI scanning more accessible to everyone while advancing our understanding of conditions like MS. The information we gather will help improve future research and treatment options.