Why Do I Need To Get Another MRI Scan?
The journey to an official diagnosis of multiple sclerosis (MS) can take years for some people, like it did for me. Some of the most common tests used to make a diagnosis include clinical exam, medical history, laboratory testing, and specialized tools such as magnetic resonance imaging (MRI), evoked potentials (EP), or vision tests to detect nerve damage or physical abnormalities.
Before I was officially diagnosed, I had undergone several of these tests multiple times. For example, I had six MRI scans between the first time my vision “seemed off” in 1994, the time I was temporarily blind in 2000, and when I lost the use of my left hand and arm in 2005. Since my diagnosis I’ve had eight additional MRI scans, each including one to three areas of the central nervous system: brain, cervical spine, or thoracic spine.
Only a few times have I questioned, “Do I really need another MRI right now?”
Top three reasons you might need another MRI
Confirm diagnosis. To diagnose MS, there must be objective evidence that damage to myelin — the fatty substance that covers and protects nerve cells — occurred in two different locations of the central nervous system at two different points in time. The use of gadolinium— a contrast agent injected into a vein during an MRI scan — can help the radiologist distinguish between new “active” lesions and old lesions.
If both active and non-active lesions are seen on scans conducted during a single session, then MS diagnostic criteria may be met. However, it is more likely that repeat MRI scans will be needed to demonstrate that multiple (many) scleroses (scars) have occurred at different points in time and confirm a diagnosis of MS.
Before MRIs became more widely available in the 1990’s, neurologists relied on other testing measures, such as EP, cerebrospinal fluid analysis, wait-and-see approach for repeat attacks, or the “hot bath” test. As treatment options were limited before that time, neurologists might not even tell a patient they had MS.
“When to tell the patient the diagnosis is controversial. My policy is to do so without delay when the diagnosis becomes definite, except in the small group of patients who genuinely do not wish to know: careful assessment of the patient’s personality and circumstances is a necessary preliminary to reaching such a decision.” — Ian McDonald, BMJ. Diagnosis of multiple sclerosis. 1989;299:635–637.
Monitor disease activity. The correlation between MS lesions, relapse, and symptoms can be weak at times. Often patients with MS may have a relapse but not show new lesions on MRI scan; or patients may have “clinically silent” lesions that do not result in symptoms or relapse. Although MRI scans may not clearly reflect a patient’s clinical experience, they can be important for monitoring the disease.
In development of disease-modifying therapies for MS, researchers have evaluated treatment success by the amount of reduction of annualized relapse rates and delayed progression of disability in people with MS. It is by these measures that the Food and Drug Administration (FDA) approves drugs for MS. Researchers and clinicians have begun to push for a higher standard of treatment response, called no evidence of disease activity (NEDA), in patients with MS.
Research suggests that even clinically silent lesions can contribute to long-term negative outcomes in MS. Although you may not experience many relapses or new symptoms, your disease may be active. One way to keep tabs on this is through routine MRIs. New MRI guidelines released in 2015 recommend that “routine brain MRI should be considered every six months to two years for all patients with relapsing MS.”
Make informed treatment decisions. If you are having lots of relapses, it may be outwardly apparent that your current disease-modifying therapy (DMT) isn’t working as well as it should for you. If you are developing new lesions or are experiencing increased disability, your DMT may not be the right one for you.
Each of us are unique and our bodies respond differently to treatment. When I was diagnosed, there were five MS treatments available, three of which worked in the same way. Now we have 14 treatment options that work in nine different ways. If one treatment doesn’t work for you, another one may.
Routine MRI can also show that your treatment is working well for you. My last five MRIs have shown that my disease is stable; no new lesions and older lesions that are consistent with prior demyelinating activity and damage. Although I may wonder to myself, “what’s the point? My MRIs haven’t changed significantly in six years,” it is helpful to have thorough documentation for my medical records to compare if things begin to change.
Consider this. You wouldn’t refuse a blood pressure test just because results were fine the last three times it was tested because uncontrolled high blood pressure (hypertension) can cause serious heart damage. Likewise, uncontrolled MS disease activity can result in serious neurological damage over time.
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