MRI scans are the best test we have had to help make a diagnosis of Multiple Sclerosis and monitor the disease.
But some lesions in white matter come from other stresses to brain like aging, hypertension, stiff blood vessels and diabetes and we need to get better at identifying lesions specific to MS.
Also MRI does not tell us everything about the lesion which is why we are looking for more advanced imaging techniques. It is why sometimes you will ask how could my MRI be stable when I feel I am getting worse.
The MRI lesion we see does not tell us whether it is just due to inflammation or whether it has remyelinated or if some of it is a scar. It does not tell the state of the axon, whether it is surviving or if it has been permanently injured.
We have been looking for better markers on MRI and think we have found some!
We are looking for central veins and paramagnetic rims.
Since MS lesions form around veins there are new sequences where we look for central veins to see if lesions are due to MS or other stresses to brain
When new lesions form, myelin is degraded and myelin has a lot of iron in it. In about 30% of lesions some of this iron stays at rim of lesion for 3-5 yrs and we can see it on different sequences. These paramagnetic rim lesions seem to correlate with more disability over time
Since new lesions only contrast enhance for 3-4 weeks we are now doing MRI follow up scans without contrast and comparing them to prior MRIs and using these newer sequences. We can still tell if there have been new lesions compared to your last MRI but maybe we can also tell if it is due to your MS or not.
We are using these new sequences which are more informative and we hope will improve our standard MRI biomarker as we continue to use them over the next several years.
Nancy Nealon, MD