Lesions are basically scars caused by any number of things; trauma, illness, or infection, just to name a few. MS lesions are scars caused by the demyelination of nerves in the spinal cord and brain. As more damage occurs, the number of lesions increases, which tends to be the case as Multiple Sclerosis advances.
Doctors are able to determine how much damage is done by the number and size of the lesions seen. MRI pictures of MS lesions help a doctor get a better idea of how much demyelination has already occurred and which lesions have reactivated. Of course there are always instances where nerves have been damaged and then remyelinated themselves. When this happens, the lesion may not show up at all.
The effects of MS Lesions on Brain
An abundance of lesions on the brain can sometimes cause certain symptoms to arise. Brain lesions cause changes in the thought process, depression, impaired speech, a loss of coordination, and a loss in judgment. A combination of these effects or only one may occur in MS patients. The reason MS lesions on the brain can cause these physical alterations to occur is from the demyelination of nerves.
Not all signs and symptoms of MS are connected to the lesions. For example, fatigue is associated with MS, but it has nothing to do with the amount of lesions appearing on the brain during an MRI scan. In fact, the current MRI MS lesions images will often show scarring which don’t have anything to with symptoms present during the time of the scan.
How MS Lesions on MRI Scans are Deciphered
When an MRI of MS lesions is taken, the scars could already be relatively old. The age of the lesion can sometimes be determined by how well they show up on the scan. There are always scars that don’t appear, no matter how old they are and also active lesions won’t generally show up because not enough demyelination has taken place.
The brainstem is where symptomatic lesions are found and they will show up as very bright areas on an MRI scan. Older areas where lesions have been reabsorbed will appear black. These dark spots appear when MS has progressed to an advance stage. Usually two MRIs are taken and compared to detect MS lesions. After the first regular scan is complete, an MRI contrast is taken. As these two are compared, old lesions that have been reactivated will be noticeable.
