MRI Is the Preferred Method of Imaging the Brain
MRI (magnetic resonance imaging) is the preferred method of imaging the brain to detect the presence of plaques or scarring caused by MS. This technology is able to detect lesions in different parts of the central nervous system and differentiate old lesions from those that are new or active.
Still, the diagnosis of MS cannot be made solely on the basis of MRI. There are other diseases that cause lesions-areas of damage-in the brain that look like those caused by MS. There are also spots found in healthy individuals, particularly in older persons, which are not related to any ongoing disease process.
On the other hand, a normal MRI cannot rule out a diagnosis of MS. About 5% of people who are confirmed to have MS on the basis of other criteria, do not show any lesions in the brain on MRI. These individuals may have lesions in the spinal cord or may have lesions that cannot be detected by MRI. Eventually, however, the vast majority of people with MS will have brain and/or spinal lesions on MRI. The longer the MRI remains negative, the more questionable the diagnosis becomes. If the MRI findings continue to be negative more than a year or two after the initial diagnosis is made, every effort should be made to identify another possible cause for the symptoms.
Other Tests Are Sometimes Needed
It is not usually necessary to do all diagnostic tests for every patient. If, however, a clear-cut diagnosis cannot be made based on the tests above, additional tests may be ordered. These include tests of evoked potentials, cerebrospinal fluid, and blood.
Evoked potential (EP) tests are recordings of the nervous system's electrical response to the stimulation of specific sensory pathways (e.g., visual, auditory, general sensory). Because demyelination results in a slowing of response time, EPs can sometimes provide evidence of scarring along nerve pathways that is not apparent on a neurologic exam. Visual evoked potentials are considered the most useful for confirming the MS diagnosis. Cerebrospinal fluid, sampled by a spinal tap, is tested for levels of certain immune system proteins and for the presence of oligoclonal bands. These bands indicate an immune response within the central nervous system. Oligoclonal bands are found in the spinal fluid of about 90-95% of people with MS. Since, however, they are present in other diseases as well, oligoclonal bands cannot be relied on as positive proof of MS.
While there is no definitive blood test for MS, blood tests can rule out other causes for various neurologic symptoms. Some other conditions that cause symptoms similar to those of MS are Lyme disease, a group of diseases known as collagen-vascular diseases, certain rare hereditary disorders, and AIDS.
The Importance of a Timely and Accurate Diagnosis
Making the diagnosis of MS as quickly and accurately as possible is important for several reasons: People who are living with frightening and uncomfortable symptoms want and need to know the reason for their discomfort. This enables them to begin the adjustment process and relieves them of worries about other diseases such as cancer. Since we now know that permanent neurologic damage can occur even in the earliest stages of MS, it is important to confirm the diagnosis so that the appropriate treatment(s) can be initiated as early in the disease process as possible.
National Multiple Sclerosis Society Can Provide Referrals. If some, but not all of the test results suggest MS, and other causes for these results have been ruled out, a physician may diagnose "possible MS" and repeat testing at a future date. The National MS Society does not require people to have a definite diagnosis before offering support, information, and services. Chapters of the National MS Society can also provide referrals to area physicians who have experience diagnosing and treating MS.
At this point, you have learned about your disease or condition and how it can be treated or managed. Your information may have come from the following sources:
Your doctor.
Second opinions from one or more other doctors.
Other people who are or were in the same situation as you.
Information sources such as Web sites, health or medical libraries, and non-profit groups.
Work With Your Doctor To Make Decisions
When you are ready to make treatment decisions, you and your doctor can discuss:
Which treatments have been found to work well, or not work well, for your particular condition.
The pros and cons of each treatment option.
Make sure that your doctor knows your preferences and feelings about the different treatments—for example, whether you prefer medicine over surgery.
Once you and your doctor decide on one or more treatments that are right for you, you can work together to develop a treatment plan. This plan will include everything that will be done to treat or manage your disease or condition—including what you need to do to make the plan work. Remember, being an active member of your health care team helps to reduce your chances of medical mistakes, and it helps you get high-quality care.
Take Another Deep Breath
You have taken important steps to cope with your diagnosis, make decisions, and get on with your life. Remember two things:
Call on others for support as you need it.
Make use of evidence-based information for any future health decisions.