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Diagnosis: MRI Scan Image

Diagnosis (ref m22)

Diagnosis of MS is based on medical history, symptoms and confirmed by further tests:

  • MRI scan of the brain and spine
  • evoked potential tests
  • test of cerebrospinal fluid (CSF) for evidence of inflammation

If an individual has suffered two separate episodes of symptoms characteristic of MS and has consistent abnormalities on physical examination, MS can usually be diagnosed without the need for further neurological tests. However, if an individual has had only one episode of symptoms, neurological tests can be used to help confirm a diagnosis of MS at an earlier stage of disease.

Magnetic resonance imaging (MRI) of the brain and spine is widely used to confirm a diagnosis of MS. This technique uses strong magnetic fields to produce an image which can reveal damage to the white matter of the brain, characteristic of MS. (figure 5) Demyelination can be detected even when the damage is not sufficient to cause clinical symptoms.

MRI scan of the brain with typical MS lesions

Figure 5. MRI scan of the brain with typical MS lesions. Round-to-oval-shaped MS lesions can be seen (circled in red) around the butterfly shape (dark)


Evoked potential tests measure the speed with which messages are transmitted from specific parts of the body (such as the eyes, ears or skin) to the brain. If demyelination has occurred, transmission of the electrical signals along the neurones is slowed down and this can be detected by evoked potential tests.

A third test used to confirm a diagnosis of MS is to determine whether antibodies are present in the cerebrospinal fluid (CSF), the fluid which surrounds the brain. Antibodies are present in 85–9 5% of patients with MS (although they can also be detected in patients with other disease). In order to carry out this test a lumbar puncture is performed under local anaesthetic. A needle is inserted into the lower back to collect a sample of CSF to test for antibodies.

Stages in diagnosis

Did you know?

Multiple Sclerosis is a disease of unknown origin that affects the central nervous system.

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Biogen Idec

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Page last updated: 22 Jun 2010

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