New Consensus Guideline on Clinical MRI Use in MS
ORLANDO, FL — An updated consensus guideline on routine clinical use of magnetic resonance imaging (MRI) in multiple sclerosis (MS) has been released collaboratively by three international expert groups.
The guideline represents a collaboration between the Consortium of Multiple Sclerosis Centers (CMSC), the European-based Magnetic Resonance Imaging in Multiple Sclerosis (MAGNIMS), and North American Imaging in Multiple Sclerosis (NAIMS).
Among its recommendations for improving diagnosis and management of MS is the establishment of much-needed ways to boost protocol adherence.
“The key part of these recommendations that we want to emphasize is how important it is for them to be used,” David Li, MD, University of British Columbia, Vancouver, Canada, and cochair of the MRI guideline committee, told Medscape Medical News.
Li noted that there was a widespread lack of adherence among MRI centers to comply with the 2018 CMSC guidelines in imaging for MS. This potentially compromised clinicians’ ability to identify lesions that allow for earlier and confident diagnoses and to monitor for disease changes that may necessitate the initiation or change of therapy, he said.
“The key to being able to know that brain changes have occurred in patients over time is to have scans that have been performed using standardized protocols — to be certain that the change is truly the result of a change in disease activity and progression and not erroneously due to differences resulting from different MRI scanning procedures,” he said to attendees at the virtual CMSC 2021 Annual Meeting.
The guideline was also published this summer as a position paper in Lancet Neurology.
The new guideline covers a broad range of imaging topics, with key areas of focus including the use of three-dimensional (3D) imaging, when and when not to use gadolinium contrast, and spinal cord imaging.
For example, a 3 Tesla magnet strength is preferred when imaging the brain with MRI because of its increased sensitivity for detecting lesions — but a minimum magnet strength of at least 1.5T can also be used. For the spinal cord, there is no advantage of 3T over 1.5T, the guidelines note.
Other recommendations include:
Core sequences for the brain should include sagittal and axial T2 weighted 3D fluid-attenuated inversion recovery (FLAIR), along with axial T2-weighted and diffusion-weighted sequences
3D acquisition, which is now available on most scanners, is preferable to 2D acquisitions
Use of the subcallosal plane for consistent and reproducible alignment of axial scans is again emphasized, as it allows for easier and more confident comparison of follow-up studies to detect changes over time
At least two of three sagittal sequences are recommended for spinal cord MRI
The judicious use of macrocyclic gadolinium-based contrast agents (GBCA) is reemphasized because of its invaluable role in specific circumstances
However, for routine follow-up monitoring for sub-clinical disease activity, high quality nonenhanced scans will allow for identification of new or enlarging T2 lesions without the need for GBCA
A new baseline brain MRI scan without gadolinium is recommended at least 3 months after treatment initiation, with annual follow-up scans without gadolinium
For the diagnosis of MS, imaging of the entire spinal cord, as opposed to only the cervical segments, is recommended for the detection of lesions in the lower thoracic spinal segments and conus. However, 1.5T scans are acceptable in that imaging, as 3T scans provide no advantage. For routine follow-up monitoring, spinal cord MRI is optional.
“The current guidelines do not recommend routine follow-up spinal cord MRI, as it remains technically challenging and would disproportionately increase the scanning time, however experienced centers have the option to do so as a small number of asymptomatic spinal cord lesions do develop on follow-up,” the authors note.
“However, follow up spinal cord MRI is recommended in special circumstances, including unexpected disease worsening and the possibility of a diagnosis other than multiple sclerosis,” they add.
Although the central vein sign has gained significant interest as a potential biomarker of inflammatory demyelination to help distinguish between MS and non-MS lesions, the 2021 protocol does not currently recommend imaging for the feature. However, those recommendations may change in future guidelines, the authors noted.
Low Protocol Adherence
The ongoing lack of adherence to guidelines that has resulted in frustrating inconsistencies in imaging was documented in no less than four studies presented at the meeting. They showed compliance with standard protocols to be strikingly poor.
Among the studies was one presented by Anthony Traboulsee, MD, professor and research chair of the MS Society of Canada, and from the University of British Columbia in Vancouver. Findings showed that only about half of scans acquired in a real-world dataset satisfied 2018 CMSC Standardized Brain MRI recommendations.
“Of note was that all the scans that were compliant were acquired in 3D while none of the 2D acquired sequences were adherent,” Li commented.
Another study assessed use of standardized MRI protocols in a pragmatic, multisite MS clinical trial, the Traditional vs Early Aggressive Therapy in Multiple Sclerosis (TREAT-MS) trial. Results showed that, upon enrollment, only 10% of scans followed CMSC guidelines for all three structural contrasts.
In that study, when the images provided by Johns Hopkins University Medical School were excluded, that figure dropped to 2.75% of remaining scans that met the criteria.
“Despite the importance of standardization of high-quality MRIs for the monitoring of people with MS, adoption of recommended imaging remains low,” the investigators write.
Resistance to Change?
Commenting on the research and new guideline for Medscape Medical News, Blake E. Dewey, PhD Student, Department of Electrical and Computer Engineering at Johns Hopkins University, Baltimore, Maryland, speculated that the noncompliance is often simply a matter of resistance to change.
“There are a number of reasons that are given for the retention of older, non-compliant MRI scans at different institutions, such as timing and patient throughput; but in my mind the issue is institutional inertia,” he said.
“It is difficult in many instances to get the clinician [radiologist] and institutional buy-in to make these kinds of changes across the board,” Dewey noted.
“The most common protocol that we see acquired is a set of 2D, low resolution images with gaps between slices. These are simply not sufficient given modern MRI technology and the needs of MS clinicians,” he added.
Importantly, Dewey noted that through direct communication with imaging staff and practitioners in the trial, compliance increased substantially — nearly 20-fold, “indicating a real possibility for outreach, including to commonly used outpatient radiology facilities.”
The updated MAGNIMS-CMSC-NAIMS MRI protocol is beneficial in providing “simple, reasonable guidelines that can be easily acquired at almost any imaging location in the U.S., and much of the rest of the world,” he said.
“As imaging researchers, we often reach for more that is needed clinically to properly diagnose and monitor a patient’s disease,” Dewey added. “This updated protocol has ‘trimmed the fat’ and left some discretion to institution, which should help with compliance.”
Dewey said he also encourages imaging professionals to consider performing the sequences described as “optional” as well.
“Some of these are useful in measuring potential biomarkers currently under extensive validation, such as brain volumetrics and the central vein sign, that may help patient populations that are currently underserved by more traditional imaging, such as progressive patients and patients that could be potentially misdiagnosed,” Dewey said.
Spreading the Word
In the meantime, as part of its own outreach efforts, the CMSC is providing laminated cards that detail in simplified tables the 2021 updated MRI protocol. This makes it easy for centers to access the information and patients to help improve awareness of the protocol.
“We are urging clinicians to provide the cards to their MS patients and have them present the cards to their imaging center,” Li said. “This effort could make such an important difference in helping to encourage more to follow the protocol.”
Clinicians and patients alike can download the MRI Protocol card from the CMSC website.
Consortium of Multiple Sclerosis Centers (CMSC) 2021 Annual Meeting. Abstract IMG03. Presented October 25, 2021.
Li and Dewey have reported no relevant financial relationships.
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