The 2021 Magnetic Resonance Imaging in Multiple Sclerosis (MAGNIMS), Consortium of Multiple Sclerosis Centres (CMSC), North American Imaging in Multiple Sclerosis Cooperative (NAIMS), provided updated consensus recommendations on magnetic resonance imagining (MRI) in patients with multiple sclerosis (MS), which can be found in The Lancet Neurology.
A team of researchers for the MAGNIMS, CMSC, and NAIMS study groups generated the guidelines to provide updates on MRI use for the diagnosis, prognosis, and treatment monitoring of MS with detailed guidance on the use of standardized MRI protocols, the use of intravenous gadolinium-based contrast agents (GBCAs), and standardized reporting. They also made recommendations on the use of MRI in patients with MS who are children, are pregnant, or are in postpartum period. Finally, they made recommendations regarding new MRI techniques with the potential for future clinical importance.
Use of MRI for Establishing MS Diagnosis
The use of 3 dimensional (3D) acquisition techniques, as opposed to 2D techniques, are preferred and are becoming more clinically available for the detection of new lesions when comparing serial MRI scans. Sagittal 3D T2-weighted fluid-attenuated inversion recovery (FLAIR) is considered the core sequence for MS diagnosis and monitoring due to its high sensitivity. When high quality 3D FLAIR images are unattainable, the use of high quality 2D pulse-sequences can be used as an alternative.
Although 3 T scanners have a higher detection rate for MS lesions and may provide faster acquisition compared with lower magnetic field strengths, the use of 1.5 T scanners are still sufficient for the detection of brain lesions at the time of diagnosis. There is currently no evidence suggesting that 3 T scanning leads to earlier MS diagnoses. However, scanners with less than 1.5 T field strengths are not recommended. 7 T, which is not often available and used mainly for research purposes, is also not recommended in clinical practice at this stage.
During the initial investigation of MS to show dissemination in time and to exclude alternative diagnoses, the use of GBCAs is essential. Double and triple doses of GBCAs are not recommended in clinical practice due to safety concerns, and the time delay between contrast administration and T1-weighted acquisition should be the same during follow-up scans and ideally 10 minutes, but no less than 5 minutes.
For additional or advanced MRI, the panel noted that diffusion-weighted imaging cannot substitute gadolinium an active inflammation marker. They did not recommend dedicated optic nerve MRI except for patients with atypical clinical features or when differential diagnoses of neuromyelitis optica spectrum disorders is made.
When the first MRI does not fulfill the criteria, brain MRI every 6 to 12 months in clinically isolated syndrome and subclinical MS radiologically isolated syndrome is recommended. Identical image acquisition is strongly recommended. Spinal cord MRI, however, is not routinely recommended and gadolinium is not recommended.
Use of GBCAs in the Diagnosis and Monitoring of MS
In diagnosis, the use of GBCAs is recommended to present the dissemination from the baseline MRI scan, to help with differential diagnoses, predict disease activity and some disease progression, and to phenotype patients with progressive disease.
In monitoring disease, some instances in which the use of GBCAs is recommended are the first year of follow-up if there is no newly obtained baseline MRI scan, if there is a need to identify or confirm clinical disease activity in patients without a recent reference brain MRI scan, and for patients with diffuse and confluent chronic MS lesions.
The investigators did not recommend the use of GBCAs in new baseline MRI scan, in short follow-up MRI for the confirmation of disease activity in patients with isolated MRI activity on previous MRI scan, for progressive multifocal leukoencephalopathy screening, or in pregnant patients (strictly contraindicated).
The 2021 evidence-based MAGNIMS-CMSC-NAIMS recommendations aimed to simplify and condense brain MRI protocols for monitoring MS to ensure easier use than previous guidelines. The guideline authors also recommended that new baseline MRI scans without gadolinium should be provided at least 3 months after treatment initiation with annual follow-up scans without gadolinium.
Compared with previous guidelines, a new recommendation was the reduction of repeated use of even macrocyclic GBCAs. Additionally, the authors noted that there is not enough supporting evidence for the use of spinal cord MRI for routine follow-up in monitoring MS disease activity; however, spinal cord MRI is still recommended for diagnosis.
Recommendations for diagnosis, prognosis, and monitoring disease activity are generally similarly recommended in both pediatric and adult patients with MS.
“[Standardization] and implementation of new and potentially more sensitive and specific imaging techniques than those that are currently used represent  of the greatest challenges but also  of the greatest opportunities in the near future, particularly as new treatments focusing on neuroprotection, remyelination, and neuronal repair emerge,” the authors concluded.
For more detailed information, see the original consensus recommendations.
Disclosure: Multiple authors declared affiliations with the pharmaceutical industry. Please refer to the original article for a full list of disclosures.
Wattjes MP, Ciccarelli O, Reich DS, et al. 2021 MAGNIMS-CMSC-NAIMS consensus recommendations on the use of MRI in patients with multiple sclerosis. Lancet Neurol. Published online June 14, 2021. doi:10.1016/S1474-4422(21)00095-8