CMSC MRI Guidelines Evolve Into International Consensus Protocol

Nancy A. Melville

June 16, 2020

Proposed updates to guidelines for magnetic resonance imaging (MRI) in multiple sclerosis (MS) patients are in the works to make the Consortium of Multiple Sclerosis Centers' (CMSC) protocol and other international guidelines more similar, with the hope that internationally accepted consensus guidelines will improve lagging conformity to the recommendations.

"We've always envisioned the guidelines as being international, but now we have harmony with the groups, so this is truly a global protocol," Anthony Traboulsee, MD, a professor of neurology and director of the MS clinic and NMO clinic at the University of British Columbia in Vancouver, said in presenting the proposed updates during the 2020 Virtual Annual Meeting of the CMSC.

The updates reflect the input of an international expert panel convened by the CMSC in October 2019, made up of neurologists, radiologists, magnetic resonance technologists, and imaging scientists with expertise in MS.

Attendees represented groups including the European-based Magnetic Resonance Imaging in MS (MAGNIMS), North American Imag­ing in Multiple Sclerosis Cooperative, National MS Society, Multiple Scle­rosis Association of America, MRI manufacturers, and commercial image analysis.

While the mission was to review and update the current guidelines, an important overriding objective was to boost universal acceptance and improve the utilization of the protocol, which research shows is surprisingly low.

According to one poster presented at the meeting, a real-world MRI dataset of 1233 sessions showed only 8% satisfied criteria for the T1 sequence outlined in the 2018 guidelines, and only 7% satisfied criteria for the T2 sequence.

"In a real-world MRI data­set of patients with MS, the conformance to the CMSC brain MRI guide­lines was extremely low," concluded the authors, who were with Icometrix, in Chicago and Belgium.

David Li, MD, also of the University of British Columbia and co-chair of the MRI guideline committee, said the nonconformity has important implications.

"Nonstandardized scans, with inconsistent slice thickness and gaps, nonstandardized slice acquisition (not in the subcallosal plane), and incomplete brain coverage, all contribute to scans that are difficult to compare," he told Medscape Medical News.

Those factors, he said, "allow for assessment of new lesions and lesion activity that are invaluable for diagnosis as well as determining the effectiveness of therapy or the need for initiating/changing therapy."

Traboulsee said the lack of adherence to guidelines may simply have to do with a mistaken perception of complexity.

"Part of the challenge is MRI centers don't realize how easy it is to implement these guidelines," he said in presenting the proposed updates.

Traboulsee noted that the CMSC has been working with manufacturers to try to incorporate the protocol into the scanners "so that it's just a button to press for the MRI."

"I think that will get us over a major hurdle of adaptation," Traboulsee said. "Most radiologists said once they started using it they were really happy with it."

"They found they were using it beyond MS for other basic neurologic imaging, so just raising awareness and making things more of a one-step process for individuals to use will be helpful," he said.

Repositioning Consistency is Key

Among key suggestions that the expert panel proposed for guideline updates include the use of the subcallosal plane for consistent repositioning, which should allow for more accuracy and consistency in the identification of lesions in MS, Traboulsee said.

"A major change reflecting improvements in MRI technology is the ability to acquire high resolution 3D images and that's particularly helpful with fluid attenuation inversion recovery (FLAIR) sequences, which is what we do to identify lesions," he explained.

"The repositioning along the subcallosal line is important because it allows us to easily compare studies over time."

"It takes very little time but allows us to prepare studies over time much more easily," he said.

Central Vein Sign

Another update is the establishment of a new category of optimum plus sequences allowing for the monitoring of brain atrophy and identifying lesions with a central vein sign, which has gained high interest as a marker on 3T MRI of demyelinating plaques in MS.

As described in recent research, the central vein sign shows high accuracy in differentiating between MS and non-MS lesions.

"Many people have a few white spots on neuroimaging, but with MRI so much more available around the world, many of them are being misdiagnosed with MS," Traboulsee said.

"But the central vein sign, using a very simple MRI technique, can identify lesions with a vein in the center that (distinguishes them as) MS lesions."

Though the process is still several years from routine clinical use, the proposed update would better implement susceptibility weighted imaging, which has traditionally been used for functional MRI.

PML Surveillance

The updates also include recommendations to help in the detection of the rare but potentially serious complication of some disease-modifying therapies of progressive multifocal leukoencephalopathy (PML).

"We need a very quick and comprehensive way to monitor patients for PML before symptoms develop," Traboulsee said.

"The sequences we recommended were based on expert opinion of people who have worked quite a bit with PML in MS, and if one wants to survey for PML it's only about a 10-minute scan."

International Protocol

Corey Ford, MD, a professor of neurology and director of the MS Specialty Clinic at the University of New Mexico Health Sciences Center in Albuquerque, commented that with imaging playing such an important role in MS, the lack of adherence to the protocol can be a significant hindrance.

"MRI is the most important imaging tool we have in the diagnosing and management of MS, but...it's quite amazing how different the sequences that are used can be when imaging centers are asked to image someone with a diagnosis of MS, so it's a problem," he told Medscape Medical News.

Ford speculated that part of the problem is simply inertia at some imaging centers.

"Practices will have been programmed into their protocol for a long time, so when a patient comes in for imaging regarding MS, they may [turn to] their typical sequence," he said.

"There is an inertial barrier to upgrading that sequence, which can involve testing it out on the machine, training the techs to do it that way, and interpreting it for the physician clients who requested the imaging."

In addition, there is a lack of exposure of MS imaging guidelines in the radiology literature, Ford added.

"Maybe it's a matter of giving more presentations at meetings that include radiologists, or getting the information out through the manufacturers. I think at the end of the day it could be a combination of all of those things," he said.

However, the CMSC collaboration could make a big difference, he noted.

"This is where the international protocol could be important in terms of making all of this happen," Ford said.

"What we're seeing is the confluence of representatives of the US and European centers hash out a consensus, and if it's international, I think that adds a lot of weight to an eventual implementation on a wider basis."

"I think the group has done a stellar job and we should not try to be too focused on adding everyone's little tweak," he noted.

"If we can get a good baseline foundational imaging sequence that can be implemented worldwide, we would be much better off."

The CMSC updated imaging Guidelines are expected to be published in coming months. The most recent previous updates are available online.

Traboulsee disclosed relationships with Biogen, Chugai, Roche, Sanofi, Teva. Ford and Li have disclosed no relevant financial relationships.

2020 Virtual Annual Meeting of the Consortium of Multiple Sclerosis Centers (CMSC): Abstract DAM06, IMG01.

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