Clinically Stable MS and Magnetic Resonance Imaging
What is clinically stable multiple sclerosis?
As most of you might be aware, the most common form of multiple sclerosis is relapsing-remitting MS (RRMS). In RRMS, people may go through periods of attacks (called relapses) or periods of remission (where the disease does not appear to be progressing). The times of remission can vary. Increasingly, with new medications, people can have extended periods of remission. During these periods, they often find that they don’t develop new symptoms and their existing ones stay the same. This is referred to as clinically stable MS.
What is magnetic resonance imaging (MRI)?
Magnetic resonance imaging or MRI is an imaging technique that is useful for collecting pictures of organs and tissues, such as the brain. MRI is used as a tool in MS for diagnosis, monitoring disease progress and measuring the success of treatments. It allows for the detection of lesions (area of myelin damage) in the central nervous system, however, only those that occur in white matter. It has been recently shown that many lesions occur in the grey matter and that current MRI techniques cannot detect these.
Should clinically stable individuals get regular MRI scans?
It has been routine neurological practice to continue to obtain MRI images for people with MS, even those that are clinically stable. It is thought that this is useful, as ‘silent’ damage can still be occurring in these individuals –that is, new damage to the myelin without any signs or symptoms. However, very few studies have been done to provide evidence for this.
Recently, a study was performed by researchers from the Providence Brain and Spine Institute to investigate this question. Using collected data, they analysed the data from 436 people with clinically stable MS who had regular MRI scans over a 2-3 year period. In this, they found that 16.7% did have changes on their MRI scans – either as new, enhancing or enlarged lesions. In this group, 26% (4.4% of the total group) changed their medication based on the differences observed on their MRI images.
This information could be viewed in one of two ways. Firstly (as the authors did), it could be concluded that this provides evidence that disease activity can still be occurring in people with clinically stable MS, meaning the use of regular MRI scans is justified and necessary to ensure their best outcomes.
On the other hand, the low numbers of people with clinically stable MS that had changes on their MRI, combined with the fact that even this very rarely resulted in any changes in treatment plan, could be used as a reason to argue against regular scanning.
It should be noted that this data was obtained using either a 1.5T or a 3.0T MRI. These less sensitive scans may have missed some disease activity, which would affect the overall results. These results must also be viewed in the context of research into the safety of MRI contrast agent, gadolinium, which has been found to remain deposited in brain tissue. The long-term safety implications of this are still unknown.
The pros and cons of having regular MRI scans should be discussed with your neurologist. A clear plan should be established as to why the scans are being performed and what action will be taken if changes do appear in the images.