#ACTRIMS2022 – Iron Rim Lesions Linked to More Severe Disease

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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Iron rim lesions, or specific regions of chronic inflammation seen on MRI scans of the brain, are associated with greater disability and poorer outcomes in multiple sclerosis (MS), a study indicates.

These findings “could support the use of iron rim lesions as an imaging biomarker for disease severity and worse prognosis,” said Amjad AlTokhis, a PhD student at the University of Nottingham.

AlTokhis presented these data at the Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) Forum 2022, in the oral presentation “Longitudinal Clinical Study of Patients with White Matter Iron Rims Lesions in Multiple Sclerosis.”

MS is caused by immune system attacks on healthy parts of the brain and spinal cord. MRI brain scans are used to image disease-associated damage, which appears on scans as lesions or patches of damage and inflammation.

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Iron rim lesions, or IRLs, are a particular type of lesion characterized by a “rim” or “ring” around the lesion on an MRI scan due to an accumulation of iron-laden inflammatory immune cells called microglia. An emerging body of research suggests that IRLs may be associated with a more severe course of MS, but the prognostic utility of these imaging features is still being explored.

Researchers in U.K. reported findings on 91 MS patients who underwent highly sensitive MRI scans between 2008 and 2013.

“Our aim is to assess if the presence and number of [initial] iron rim lesions are associated with worse long-term disability,” AlTokhis said.

At the study’s start, 22 of these patients had clinically isolated syndrome (CIS), 34 had relapsing-remitting MS (RRMS), 17 had secondary progressive MS (SPMS), and 18 had primary progressive MS (PPMS).

Just under half (46%) had at least one IRL at study’s start or baseline measures — 30% had one to three iron rim lesions, and 16% had four or more. People with SPMS had the highest number of iron rim lesions, with 12 patients showing a total of 58 lesions.

Disease severity at baseline was significantly higher in patients with IRLs than without them, as evidenced by a median score of median 6.7 vs. 5, respectively, on the Age Related Multiple Sclerosis Score (ARMSS), which ranks a patient’s EDSS score of functional disability by age at time of assessment.

After a median follow-up of nine years, patients with IRLs had significantly higher median ARMSS scores than those with no IRLs (7.3 vs. 6.3), again indicating more severe disease.

Statistical analyses showed a correlation between iron rim lesions and ARMSS worsening, with high specificity but low sensitivity. Put another way, almost all of the patients with four or more IRLs experienced a substantial worsening of disability, though similar amounts of worsening also could be found in patients without IRLs.

Further analyses suggested that predicting long-term disability progression based on IRLs is more accurate than similar analyses using the number or volume of white matter lesions, which are regions of damage in parts of the brain containing nerve cell fibers.

“Our data suggest that the presence and number of iron rim lesions hold a prognostic value for long-term disability in MS, especially the presence of four or more rims,” AlTokhis concluded.

AlTokhis noted that this was a retrospective study at a single center, stressing the need for further prospective research to validate the utility of IRLs as a biomarker of potential outcomes in MS.


Editor’s note: The Multiple Sclerosis News Today team is providing in-depth coverage of the ACTRIMS Forum 2022 Feb. 24–26. Go here to see the latest stories from the conference.