Multiple sclerosis (MS) is a devastating disease affecting approximately one million people worldwide, and is the most frequent cause of disability in young adults, after car accidents. MS predominantly affects the white matter of the central nervous system. The key feature is autoimmune neuroinflammation leading to demyelination and neurodegeneration. MS exhibits an unpredictable and variable clinical course, making treatment challenging. Tomislav Babic, MD, PhD, Vice President of the Neuroscience Franchise at Worldwide Clinical Trials Inc. and Henry J. Riordan, Ph.D., Executive Vice President of Medical and Scientific Affairs and Global Lead for Neuroscience at Worldwide Clinical Trials, describe the optimisation of MRI in multiple sclerosis drug development.