MRI and CT scans are the primary imaging tests used to help diagnose MS. Lesions in the brain and spine appear as lighter or darker spots that appear different from normal tissue. Other types of diagnostic testing, such as a lumbar puncture or blood tests, can also help establish an MS diagnosis.
While general brain scans are often performed using computerized tomography (CT), MRIs are used to scan for MS; in the images, doctors are looking for abnormal white matter. “The benefit of MRI is that it shows a very good depiction of brain tissue compared to CT,” Dr. Minja says.
A brain lesion is an abnormality seen on a brain-imaging test, such as magnetic resonance imaging (MRI) or computerized tomography (CT). On CT or MRI scans, brain lesions appear as dark or light spots that don't look like normal brain tissue.
MRI scans confirm a diagnosis in over 90 per cent of people with MS. To get the image of your brain and spinal cord you'll be asked to lie down and enter a small tunnel in the centre of the MRI scanner.
Magnetic resonance imaging (MRI) is the diagnostic tool that currently offers the most sensitive, noninvasive way of imaging the brain, spinal cord or other areas of the body. It is the preferred imaging method to help establish a diagnosis of MS and to monitor the disease course.
A combination of tests is used to diagnose MS. The best test is an MRI of your brain and spinal cord to detect areas of damage. You might also need to have blood tests, a lumbar puncture and tests to measure nerve activity.
An acute MS lesion may enhance and appear simply as an enhancing white matter lesion on CT scans, but the appearance is highly nonspecific. When a highly active MS lesion is observed to enhance and possibly exerts mass effect, it can be termed tumefactive (due to the potential for misidentification as a tumor).
MS can be present even with a normal MRI and spinal fluid test although it's uncommon to have a completely normal MRI. Sometimes the MRI of the brain may be normal, but the MRI of the spinal cord may be abnormal and consistent with MS, so this also needs to be considered.
Signs and Symptoms
Characteristic lesions are located in the periventricular and juxtacortical regions, in addition to the brainstem, cerebellum, spinal cord, and optic nerve.
CT scans often miss injuries to soft tissues and other abnormalities. Therefore, a CT scan may appear normal, even though you have whiplash, brain injuries, or spinal cord injuries. The scan was made using an older machine that does not have the newest technology.
Where MRI really excels is showing certain diseases that a CT scan cannot detect. Some cancers, such as prostate cancer, uterine cancer, and certain liver cancers, are pretty much invisible or very hard to detect on a CT scan. Metastases to the bone and brain also show up better on an MRI.
MS brain lesions may appear on the brainstem—the lowest part of the brain right above the spinal cord. Among the symptoms that can appear with MS brainstem lesions are blurred or double vision, trouble swallowing, slurred speech, dizziness, coordination problems, weakness, and decreased sensation.
These include fibromyalgia and vitamin B12 deficiency, muscular dystrophy (MD), amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease), migraine, hypo-thyroidism, hypertension, Beçhets, Arnold-Chiari deformity, and mitochondrial disorders, although your neurologist can usually rule them out quite easily.
In 5 percent of the people showing clinical MS disease activity, lesions were not visible on the MRI. However, if follow-up MRI studies continue to show no lesions, the MS diagnosis should be reconsidered.
People should consider the diagnosis of MS if they have one or more of these symptoms: vision loss in one or both eyes. acute paralysis in the legs or along one side of the body. acute numbness and tingling in a limb.
In primary progressive MS, symptoms would be expected to have a gradual and insidious onset over at least 12 months by the time of diagnosis. A common first presentation of RRMS is with unilateral optic neuritis characterised by gradual onset monocular visual loss, pain on moving the eye and altered colour vision.
Sjogren's syndrome is an autoimmune disease that can mimic some of the symptoms of MS such as fatigue and joint pain.
Blood Tests: Currently, there are no definitive blood tests for diagnosing MS, but they can be used to rule out other conditions that may mimic MS symptoms, including Lyme disease, collagen-vascular diseases, rare hereditary disorders and acquired immune deficiency syndrome (AIDS).
Most symptoms develop abruptly, within hours or days. These attacks or relapses of MS typically reach their peak within a few days at most and then resolve slowly over the next several days or weeks so that a typical relapse will be symptomatic for about eight weeks from onset to recovery. Resolution is often complete.
Computed tomography (CT) scanning has a very limited role in the setting of optic neuritis. Size differences in the optic nerve can be appreciated, but this is neither sensitive nor specific.
Abnormal sensations can be a common initial symptom of MS. This often takes the form of numbness or tingling in different parts of your body, such as the arms, legs or trunk, which typically spreads out over a few days.
Why Do I Need to Get an MRI? To detect MS. MRI is considered the best test to help diagnose MS. However, 5% of people with MS do not have abnormalities detected on MRI; thus, a "negative" scan does not completely rule out MS.