Q: My sister was diagnosed 19 years ago with MS. I have MS as well. She hasn't had a symptom in eight years (and before that had been symptom-free for four years), and she has never taken any medication for her MS either. The doctor has asked her for an MRI but she sees no use in this since she has no symptoms, and it appears her MS is benign. Is there any benefit for her to have an MRI since it appears her MS is benign?

A: The fact that your sister has had almost no symptoms over the last 12 years doesn’t necessarily mean that her multiple sclerosis is benign. The diagnosis of “benign MS” can only be made at the end of someone’s life, when it can be seen in retrospect that MS did not cause gradual progressive problems or significant neurologic disability.

There can be progressive gradual changes of MS detectable on an MRI, even though the person may not be having clinical symptoms. If an MRI shows either active inflammatory changes following intravenous contrast with gadolinium or if there is a progressive accumulation of more “white matter plaques” compared to prior MRI images, then there will likely be clinical symptoms eventually. Thus, the advantage of having an MRI, even when symptoms are stable, is that the clinical situation may be just the tip of the iceberg. The MRI can be a guide as to whether or not there are any anatomical changes in the brain that may cause clinical, cognitive or physical problems in the future. Then appropriate treatment decisions can be made based on the MRI changes, whether acute or chronic.