What are the findings of a Magnetic Resonance Imaging (MRI) scan for Multiple Sclerosis (MS)?

From the Guidelines

MRI is the preferred imaging modality for diagnosing and monitoring multiple sclerosis (MS), and it should be performed at least once every year in patients with MS, with more frequent monitoring (every 3-4 months) in patients at risk of serious treatment-related adverse events. For MS diagnosis and monitoring, a standard brain and spinal cord MRI protocol should include T1-weighted images (with and without gadolinium contrast), T2-weighted images, and FLAIR sequences, as recommended by the MAGNIMS consensus guidelines 1. The use of proton density and/or T2 FLAIR and T2 weighted fast or turbo spin echo sequences can help detect new or enlarging lesions, while a gadolinium enhanced T1 weighted sequence can increase confidence in the detection of lesions with high inflammatory activity 1.

Key Considerations for MS MRI

• The specific follow-up protocol strongly depends on the purpose of the scan, such as treatment efficacy monitoring versus PML screening 1.
• Diffusion weighted scans should also be considered in patients at risk of PML 1.
• Accurate positioning of follow-up and reference scans is essential for the accurate assessment of changes in lesion size and number over time 1.
• All scans should be performed at a field strength of at least 1.5T, though higher field strengths might reveal more new lesions 1.

Technical Details for MS MRI

• For 2D sequences, slice thickness should be no more than 3 mm with an in-plane spatial resolution of 1 × 1 mm (voxel size 3 × 1 × 1 mm) 1.
• Voxels in 3D sequences should be 1 mm3 1.
• The delay between contrast administration and T1 acquisition—a minimum of 5min—can provide an opportunity to perform proton density weighted, T2 weighted and/or T2 FLAIR after contrast administration and before the T1 postcontrast acquisition, optimizing the total scanning time 1.

The MAGNIMS consensus guidelines provide a framework for the use of MRI in MS diagnosis and monitoring, emphasizing the importance of standardized protocols and regular follow-up scans to assess disease progression and treatment response 1.

From the Research

MS MRI Findings

• Spinal cord abnormalities are common in suspected MS, and may occur asymptomatic 2
• The inclusion of spinal imaging increases the sensitivity of MRI to 100% in clinically definite MS 2
• Spinal cord MRI can help rule out MS in patients with atypical brain abnormalities suggesting ischemic/vascular disease 2
• Diffuse spinal cord abnormality is often associated with primary progressive disease course and clear spinal cord symptoms 2

Diagnostic Value of Spinal Cord MRI

• Spinal cord MRI increases diagnostic sensitivity of MRI in patients with suspected MS 2, 3
• Asymptomatic spinal-cord lesions are very rare in disorders other than MS, making spinal-cord imaging valuable in the diagnostic setting 4
• Presence of asymptomatic spinal lesions may help confirm a diagnosis of MS when few or no brain lesions are present 4

Technical Considerations

• Dual echo spin echo MRI is most sensitive for the detection of spinal-cord abnormalities 4
• Quantitative MRI measures of cord size and tissue integrity could be more sensitive to the axonal loss and other pathological processes in the spinal cord than is conventional MRI 5
• Diffusion-weighted imaging and enhanced T1-weighted sequencing can show differences in MS patients with increased diffusion lesions compared with diffusion restriction 6