Is Magnetic Resonance Imaging (MRI) with or without contrast indicated to rule out Multiple Sclerosis (MS)?

From the Guidelines

MRI with contrast is the preferred method for ruling out multiple sclerosis (MS) as it provides crucial information on disease activity and helps distinguish between new and old lesions. According to the Magnims consensus guidelines on the use of MRI in multiple sclerosis 1, the use of gadolinium-enhanced T1-weighted sequence can increase confidence in the detection of lesions with high inflammatory activity.

When performing an MRI to rule out MS, the following sequences should be included:

• T1-weighted images before and after contrast
• T2-weighted images
• FLAIR sequences
• Proton density and/or T2 FLAIR and T2 weighted fast or turbo spin echo sequences to detect new or enlarging lesions
• Diffusion-weighted scans should also be considered in patients at risk of PML

The MRI should be performed at a field strength of at least 1.5T, with slice thickness no more than 3 mm and an in-plane spatial resolution of 1 × 1 mm for 2D sequences, and voxels of 1 mm3 for 3D sequences 1. The use of contrast is essential for determining disease activity and can influence treatment decisions, and patients should inform their healthcare provider about any kidney problems or allergies before receiving contrast.

Key considerations for MRI protocols include:

• Accurate positioning of follow-up and reference scans to assess changes in lesion size and number over time
• The delay between contrast administration and T1 acquisition should be at least 5 minutes to optimize scanning time
• Patients at risk of serious treatment-related adverse events may need to be monitored more frequently, for example, every 3-4 months 1

From the FDA Drug Label

Gadoteridol was evaluated in two multicenter trials of 310 evaluable patients suspected of having neurological pathology. In another multicenter study of 49 evaluable adult patients with known intracranial tumor with high suspicion of having cerebral metastases, two doses of gadoteridol were administered. The results of the non-contrast and contrast MRI scans were compared. Approximately 75-82% of the scans were enhanced, 45-48% of the scans provided additional diagnostic information, and 8-25% of the diagnoses were changed.

MRI with or without contrast to rule out MS:

• The use of gadoteridol, a gadolinium-based contrast agent, can improve the visualization of lesions and provide additional diagnostic information in patients with suspected neurological pathology, including those with multiple sclerosis (MS) 2.
• The addition of contrast can increase the number of lesions detected and improve border definition, which can be beneficial in diagnosing and monitoring MS.
• However, the FDA drug label does not provide specific information on the use of gadoteridol for ruling out MS, and the clinical decision to use contrast should be made on a case-by-case basis, taking into account the individual patient's medical history and circumstances.

From the Research

MRI with or without Contrast to Rule out MS

• The use of MRI with or without contrast is a crucial diagnostic tool for detecting multiple sclerosis (MS) lesions 3, 4.
• Contrast-enhancing lesions on T1-weighted sequences are related to (sub)acute inflammation, while new or enlarging T2 lesions reflect the permanent footprint from a previous acute inflammatory demyelinating event 3.
• The use of gadolinium-based contrast agents (GBCAs) is generally recommended in the diagnostic workup in subjects with suspected MS, but is not necessary for routine monitoring in clinical practice 3, 4.

Safety Concerns and Alternatives

• There are concerns about the long-term health effects of repeat gadolinium injections, and alternative MRI-based approaches are being explored 5, 6.
• Noncontrast quantitative MRI techniques, such as DTI-based fractional anisotropy, can assess MS lesion acuity without gadolinium 5.
• Gradient-echo-based quantitative susceptibility mapping has shown promise in discriminating enhancing and nonenhancing MS lesions 5.

Current Recommendations

• The 2021 MAGNIMS-CMSC-NAIMS consensus recommendations suggest changes in MRI acquisition protocols, including the use of three-dimensional fluid-attenuated inversion recovery as the core brain pulse sequence 7.
• The recommendations also emphasize the judicious use of gadolinium-based contrast agents for specific clinical purposes, such as diagnostic workup and monitoring of treatment effectiveness 7.
• The use of MRI in patients with MS in childhood, during pregnancy, and in the post-partum period is also addressed in the recommendations 7.