Radiologically isolated syndrome (RIS) is a neurological — brain and nerve — condition. In this syndrome, there are lesions or slightly changed areas in the brain or spine.

Lesions can occur anywhere in the central nervous system (CNS). The CNS is made up of the brain, spinal cord, and optic (eye) nerves.

Radiologically isolated syndrome is a medical finding during a head and neck scan. It’s not known to cause any other signs or symptoms. In most cases, it doesn’t require treatment.

Radiologically isolated syndrome has been linked to multiple sclerosis (MS). A brain and spine scan of someone with RIS may look like the brain and spine scan of a person with MS. However, being diagnosed with RIS doesn’t necessarily mean you’ll have MS.

Some researchers note that RIS isn’t always linked to multiple sclerosis. Lesions can happen for many reasons and in different areas of the central nervous system.

Other studies show that RIS may be part of the “multiple sclerosis spectrum.” This means that this syndrome may be a “silent” type of MS or an early sign of this condition.

A global review study found that about one-third of people with RIS showed some symptoms of MS within a five-year period. Of these, almost 10 percent were diagnosed with MS. The lesions grew or worsened in about 40 percent of people diagnosed with RIS. But they didn’t yet have any symptoms.

Where the lesions happen in radiologically isolated syndrome may also be important. One group of researchers found that people with lesions in an area of the brain called the thalamus were at higher risk.

Another study found that people who had lesions in the upper part of the spinal cord rather than in the brain were more likely to develop MS.

The same study noted that having RIS wasn’t more of a risk than other possible causes of multiple sclerosis. Most people who develop MS will have more than one risk factor. Risks for MS include:

  • genetics
  • spinal cord lesions
  • being female
  • being under the age of 37
  • being Caucasian

If you’re diagnosed with RIS, you won’t have symptoms of MS. You may not have any symptoms at all.

In some cases, people with this syndrome may have other mild signs of a nerve disorder. This includes slight brain shrinkage and inflammatory disease. Symptoms may include:

  • headache or migraine pain
  • loss of reflexes in limbs
  • limb weakness
  • problems with understanding, memory, or focus
  • anxiety and depression

Radiologically isolated syndrome is usually found by accident during a scan for other reasons. Brain lesions have become a more common finding as medical scans improve and are more frequently used.

You may have an MRI or CT scan of the head and neck for headache pain, migraines, blurred vision, a head injury, stroke, and other concerns.

Lesions may be found in the brain or spinal cord. These areas may look different from the nerve fibers and tissues around them. They may appear brighter or darker on a scan.

Almost 50 percent of adults with radiologically isolated syndrome had their first brain scan due to headaches.

RIS is rare in children, but it does happen. A review of cases in children and teenagers found that almost 42 percent had some possible signs of multiple sclerosis after their diagnosis. About 61 percent of children with RIS showed more lesions within one to two years.

Multiple sclerosis usually happens after the age of 20. A type called pediatric multiple sclerosis can happen in children younger than 18 years. Ongoing research is looking into whether radiologically isolated syndrome in children is a sign that they will develop this disease in early adulthood.

MRI and brain scans have improved and are more common. This means that RIS is now easier for doctors to find. More research is needed on whether brain lesions that don’t cause symptoms should be treated.

Some doctors are researching whether early treatment for RIS may help prevent MS. Other doctors believe that it’s best to watch and wait.

Being diagnosed with RIS doesn’t necessarily mean that you’ll ever require treatment. However, careful and regular monitoring by a specialist doctor is important. In some people with this condition, the lesions can worsen quickly. Others may develop symptoms over time. Your doctor may treat you for related symptoms, such as chronic headache pain or migraines.

Most people with RIS don’t have symptoms or develop multiple sclerosis.

However, it’s still important to see your neurologist (brain and nerve specialist) and family doctor for regular checkups. You’ll need follow-up scans to see if the lesions have changed. Scans may be needed yearly or more often even if you don’t have symptoms.

Let your doctor know about any symptoms or changes in your health. Keep a journal to record symptoms.

Tell your doctor if you feel anxious about your diagnosis. They may be able to point you to forums and support groups for people with RIS.