Physicians assess the neurological examination and MRI to determine the stability of a patient with multiple sclerosis (MS).
Many times, new lesions will enhance with contrast, which represents new inflammation derived from immune cells moving from the blood into the central nervous system (brain and spine).
If a patient has no new lesions, a physician will generally consider them stable and responding to therapy; interestingly, chronic, or older lesions are never considered in this assessment.
However, multiple recent studies have demonstrated that a group of chronic lesions continue to have inflammation at their rim, meaning the immune system within the brain is still active in these scars, which may lead to more loss of myelin.
These lesions are referred to as chronic active MS lesions and, here at Weill Cornell, we research these lesions using magnetic resonance imaging (MRI).
The MRI technique is called quantitative susceptibility mapping (QSM) and this tool can be used to assess the amount of iron in regions of the brain.
Most of the inflammatory cells in chronic MS lesions have iron, therefore we can use this type of MRI to identify these lesions; specifically, they will have a bright rim of iron on QSM.
We are currently using QSM to ask how much chronic active MS lesions contribute to clinical disability in patients with MS.
Importantly, we are working on making this a clinically and a tool to use in clinical trials of new treatments that target ongoing inflammation in the brain.
Susan Gauthier DO, MPH