Medically reviewed by Edward Tavel, MD, Medical Director · Last reviewed 22 August 2026
Multiple sclerosis is a condition in which the immune system attacks myelin, the protective sheath around nerve fibres in the brain, spinal cord, and optic nerves. Where myelin is damaged, signals travelling along those nerves slow or fail, which produces the symptoms associated with the condition. Most people are diagnosed between roughly 20 and 50 years of age, and it is diagnosed more often in women than men. The most common pattern at diagnosis is relapsing-remitting MS, in which periods of new or worsening symptoms are followed by partial or complete recovery. Other patterns progress more steadily over time. MS is not inherited in a simple way, though genetics contribute alongside environmental factors such as vitamin D status and prior viral exposure.
Because myelin damage can occur anywhere in the central nervous system, symptoms vary considerably between individuals. Frequently reported ones include blurred or painful vision in one eye, numbness or tingling, weakness, unsteadiness, dizziness, bladder changes, and a fatigue that is out of proportion to activity. Difficulty with concentration or memory is also common and often under-recognised. Diagnosis is not made on a single test. Neurologists look for evidence that damage has occurred in more than one area of the nervous system and at more than one point in time, drawing on clinical history, neurological examination, MRI, and sometimes analysis of spinal fluid or tests of nerve signal timing. Other conditions that can mimic MS are ruled out as part of that process.
MRI is central to both diagnosing and monitoring MS, because it shows areas of demyelination as bright spots on certain sequences and can reveal their distribution through the brain and spinal cord. Radiologists pay attention to where lesions sit, since particular locations are more characteristic of MS than others. An important point for anyone considering preventive imaging: bright spots in the white matter are common, particularly with age, migraine, or vascular risk factors, and the large majority have nothing to do with multiple sclerosis. A radiologist interprets such findings in the context of your age, history, and symptoms rather than in isolation. If you are weighing up a scan, it may help to read how we discuss incidental findings on an MRI, the conditions a whole-body scan can detect, or our credentials and imaging standards.
Frequently asked questions
Can an MRI diagnose multiple sclerosis on its own?
No. MRI is the most important single test, but diagnosis requires a neurologist to combine imaging with your clinical history, examination findings, and sometimes spinal fluid analysis, while excluding conditions that can look similar.
I have white matter spots on my scan. Does that mean MS?
Almost certainly not. White matter hyperintensities are common and are far more often related to age, migraine, or blood vessel changes. Their location and pattern, read alongside your symptoms, are what distinguish them.
What are usually the first symptoms?
Vision changes in one eye, often with pain on movement, are a classic early presentation. Numbness or tingling, weakness, and balance difficulty are also common first symptoms. Fatigue frequently precedes or accompanies them.
Is multiple sclerosis inherited?
Not in a direct way. Having a close relative with MS raises risk modestly above the general population, but most people with MS have no family history, and genetics appear to interact with environmental factors.
Why is the spinal cord imaged as well as the brain?
Demyelination can occur anywhere in the central nervous system, and spinal cord lesions carry particular diagnostic weight. Imaging both regions gives a fuller picture of whether damage is distributed across more than one area.
Sources
A whole-body MRI at MRI Wellness looks at the brain, spine, chest, abdomen and pelvis in a single session, without radiation or contrast dye. No referral is needed.
