Magnetic resonance imaging (MRI) in patients with multiple sclerosis (MS) is a well-established tool for diagnostic, prognostic and disease monitoring purposes.¹ Its use has been specified in various guideline papers across the globe, but the establishment of a worldwide consensus on its implementation is still a major challenge due to differences in healthcare systems and clinical practices.¹ Two major consensus papers, the Magnetic Resonance Imaging in Multiple Sclerosis (MAGNIMS) and the Consortium of Multiple Sclerosis Centres (CMSC) have been first published in 2015 and 2016, respectively and have helped neurologists to standardise image acquisition protocols and established indications for when and how to use MRI in patients with MS.^2,3 In 2021, new MAGNIMS-CMSC-North American Imaging in Multiple Sclerosis Cooperative (NAIMS) consensus recommendations have been published, incorporating new developments and addressing raised concerns in the use of MRI in MS patients.¹

New easier-to-follow guidelines recommending less use of GBCAs

In the new guidelines, the brain MRI protocol for disease monitoring purposes was shortened compared to previous versions, making it simpler and “more likely to be used than previous guidelines”, as the authors state.¹ The newly recommended MRI acquisition protocol emphasises the value of 3D-fluid-attenuated inversion recovery as the core brain pulse sequence which should improve diagnostic accuracy and ability to identify newly formed lesions. One of the major changes in comparison to older guidelines is the recommendation to reduce the repeated use of macrocyclic gadolinium-based contrast agents (GBCAs) due to the absence of convincing clinical results and risk of gadolinium accumulation in the brain. Even though the use of GBCAs continues to be important during the initial diagnosis process, a new baseline brain MRI without gadolinium is now recommended at least 3 months after treatment start, followed by annual scans without gadolinium.¹

Spinal cord MRI in routine follow ups not recommended

Authors further concluded that evidence for the benefits of spinal cord MRI in routine follow ups is lacking and that the procedure is also technically challenging.¹ Therefore, it is no longer recommended; however, spinal cord MRI is still recommended for the initial diagnosis and in cases of unexpected disease worsening. MRI is recommended equally in the diagnosis, prognosis and monitoring of paediatric and adult multiple sclerosis patients.¹

Several novel MRI techniques not yet recommended  

Even though the authors state that they appreciate accumulating evidence for the use of volumetric analysis, newly described imaging features and quantitative MRI measures they do not recommend their use at the current time.¹ The most promising one of the newly described techniques is high-resolution susceptibility-based MRI that allows the discrimination of chronic active lesions. However, this new approach still needs further validation studies to be considered a standardised method. Volume measurements have shown to be effective in the prediction of the multiple sclerosis disease course, but their accuracy and reproducibility are still a potential source of error. The implementation and harmonisation of sensitive and specific imaging techniques are currently challenging but will be great opportunities in the future as novel treatments focusing on neuroprotection, neuronal repair and remyelination are developed.¹

A major step towards better harmonisation

The new evidence-based guidelines address major concerns in the use of MRI for MS patients that have arisen recently, including the use of GBCAs. The recommended standardised protocols are a step towards better harmonisation of indications, image acquisition and interpretation in different centres across the world.¹

References

1. Wattjes MP et al. Lancet Neurol. 2021;20:653–70
2. Rovira A et al. Nat Rev Neurol. 2015;11:471–82
3. Taboulsee A et al. Am J Neuroradiol. 2016;37:394–401