Multiple sclerosis (MS). Sequence of magnetic resonance imaging (MRI) axial (horizontal) scans showing the internal structure of the head of a patient with MS. Brain MRI is used in the diagnosis and monitoring of MS. This is an inflammatory demyelinating (involving the loss of the nerve insulating material, myelin) condition of the central nervous system (CNS). Symptoms include loss of vision, extreme tiredness, and problems with balance and muscle movement. MS lesions (known as plaques) form in the CNS white matter, these can be seen as hyperintensities (bright areas) within the cerebellar and cerebral hemispheres and the brainstem on this T2 and FLAIR sequence.