From the Guidelines
Magnetic Resonance Imaging (MRI) is the primary diagnostic test for multiple sclerosis (MS), as it can detect characteristic lesions or plaques in the central nervous system, and its use is supported by the most recent and highest quality study 1.
Diagnostic Approach
The diagnosis of MS typically requires a combination of diagnostic tests, including MRI of the brain and spinal cord, lumbar puncture, evoked potential tests, and blood tests.
- MRI is the most sensitive test for detecting MS lesions, and its findings are essential for diagnosing MS according to the McDonald criteria.
- Lumbar puncture is used to analyze cerebrospinal fluid for oligoclonal bands and elevated IgG index, which indicate immune system activity within the central nervous system.
- Evoked potential tests, such as visual evoked potentials, somatosensory evoked potentials, and brainstem auditory evoked potentials, measure electrical activity in response to stimulation of specific sensory pathways and can reveal slowed nerve conduction due to demyelination.
- Blood tests are important to rule out other conditions that may mimic MS symptoms.
MRI Criteria
The MRI criteria for MS are based on the presence of focal lesions in the white matter of the central nervous system, which are considered typical for this condition in terms of distribution, morphology, evolution, and signal abnormalities on conventional MRI sequences 1.
- The MAGNIMS consensus guidelines provide a standardized brain MRI protocol to evaluate patients with suspected MS, which includes pre-contrast and post-contrast T1-weighted sequences, T2-weighted sequences, and fluid-attenuated inversion recovery (FLAIR) sequences 1.
- The assessment of lesions on MRI should take into account the specific characteristics of each individual lesion, as well as the overall patterns of lesions, to support the diagnosis of MS or other conditions 1.
Conclusion is not allowed, so the answer will continue without one.
The use of advanced MRI sequences, such as high-field MRI, can enhance the ability to distinguish key characteristics of MS, such as cortical or perivenular lesions, which can improve diagnosis 1.
- The technical developments, combined with recent discoveries about the links between lesion characteristics and MS pathogenesis, will likely drive future improvements to—and perhaps even rethinking of—current criteria.
- The diagnosis of MS should only be made in the appropriate clinical context, when onset is characterized by clinical manifestations typical of MS, and after excluding other possible diagnoses.
From the Research
Diagnostic Tests for Multiple Sclerosis
- Magnetic Resonance Imaging (MRI) is a sensitive indicator of MS lesions, with a sensitivity between 35% and 100%, and specificity between 36% and 92% 2
- Cerebrospinal fluid (CSF) oligoclonal banding has sensitivities between 69% and 91% with specificities between 59% and 94% 2
- Combination of MRI and CSF indicates enhanced sensitivity (56-100%) and specificity (53-96%) 2
- Evoked potentials, such as brain-stem auditory evoked potentials, can be more sensitive than MRI for detecting brain-stem involvement, but their overall value in diagnosis is unclear 3, 4
Comparison of Diagnostic Tests
- MRI is more sensitive than computed tomography (CT) scans in detecting MS lesions 4, 5
- MRI can demonstrate brain-stem lesions that are not visible on CT scans 5
- The combination of MRI and CSF may be the best approach for an early MS diagnosis 2
Clinical Diagnosis and Diagnostic Tests
- Clinicians use MRI findings to diagnose definite MS or eliminate MS from diagnostic consideration in 44% of cases 6
- Further laboratory testing, such as CSF analysis and evoked potential testing, can lead to a diagnosis of definite MS or elimination of MS from diagnostic consideration in an additional 13% of cases 6
- After all studies are performed, about half of patients still have a tentative diagnosis 6