The progression of MS is typically monitored with MRI scans of the brain and spinal cord. They allow your healthcare provider can determine: The number and type of lesions you have The presence or extent of nerve damage  Whether you’re responding to treatment Depending on how active and progressive your disease is, you may have them as often as every six months or only about every two years. Healthcare providers also use the Expanded Disability Status Scale and neurologic exams to track MS progression.