Magnetic resonance imaging (MRI) plays an important role in the diagnosis of multiple sclerosis and has been incorporated into the McDonald diagnostic criteria for MS. Additionally, MR has proven useful for studying the natural history of the disease and monitoring the effects of new treatments. Selective identification of lesions that contribute most to the patient's disability and clinical progression can be better achieved by using newer imaging techniques which are more sensitive in identifying abnormalities of the central nervous system related to MS and may facilitate prediction of neurologic impairment and evaluation of response to disease-modifying therapy in the future.