From the Guidelines
The best MRI technique for evaluating initial multiple sclerosis (MS) is a brain and spinal cord MRI with gadolinium contrast, including T1-weighted images, T2-weighted images, FLAIR sequences, and DWI, performed on a high-field strength magnet (preferably 3 Tesla) to detect both active and chronic demyelinating lesions. This approach is supported by the most recent and highest quality study, which emphasizes the importance of a comprehensive MRI protocol in establishing dissemination of lesions in space and time, essential for MS diagnosis according to the McDonald criteria 1.
Key Components of the MRI Protocol
- T1-weighted images (with and without contrast) to detect active lesions and breakdown of the blood-brain barrier
- T2-weighted images to detect chronic demyelinating lesions
- FLAIR sequences to detect periventricular white matter lesions, characteristic of MS
- DWI to detect acute lesions and assess disease activity
- Imaging of the spinal cord, as approximately 80-90% of MS patients have spinal cord lesions
Importance of High-Field Strength Magnet
The use of a high-field strength magnet (preferably 3 Tesla) is crucial for optimal resolution and lesion detection, as it allows for better visualization of small lesions and improved diagnostic accuracy 1.
Timing of MRI
The MRI should ideally be performed before starting any treatment, as steroids or disease-modifying therapies can affect lesion enhancement and potentially alter the diagnosis 1.
Interpretation of MRI Scans
Interpretation of the MRI scans should be performed by trained (neuro)radiologists or clinicians deeply familiar with the features of multiple sclerosis and disorders considered in the differential diagnosis, to ensure accurate diagnosis and treatment planning 1.
From the Research
MRI Techniques for Evaluating Initial MS
- The use of thin-section, sagittal, fast fluid-attenuated inversion-recovery (FLAIR) magnetic resonance (MR) imaging is superior to conventional axial spin-echo (SE) imaging for detection of MS plaques in the brain 2.
- Sagittal thin-section fast FLAIR is better than SE in 37% of cases, equal to SE in 63%, and never worse than SE 2.
- In patients with clinically suspected MS, fast FLAIR images showed abnormalities consistent with MS in 43% of patients considered to have normal SE images 2.
Comparison of MRI Techniques
- A study comparing diffusion-weighted imaging and enhanced T1-weighted sequencing in patients with MS found that patients in the increased diffusion group were significantly more than in the diffusion restriction group 3.
- The use of T2-weighted difference imaging can define MS disease activity more sensitively than traditional measures of net change in T2-weighted lesion volume 4.
- Spinal cord MRI provides relevant additional information to brain MRI in understanding MS pathophysiology, allowing an earlier and more accurate diagnosis of MS, and identifying MS patients at higher risk to develop more severe disability 5.
Spinal Cord MRI in MS
- Spinal cord MRI is highly recommended in the clinical evaluation of patients suspected of having MS, and can increase sensitivity and possibly specificity for MS 6.
- Advanced MRI techniques, such as spinal cord atrophy and diffusion tensor imaging, can better evaluate the associations between spinal cord abnormalities and the accumulation of clinical disability 5.
- The role of spinal cord assessment could evolve in the future to improve monitoring of disease progression and treatment effects 5.