Dr. Timothy Lim, Dr. Suradech Suthiphosuwan, and Dr. Jiwon Oh started their research using an advanced MRI technique that was sensitive to iron detection.
That sensitivity opened a window into the brain that hadn’t existed before, revealing two unique features around certain MS-related brain lesions: a central vein sign and something called a paramagnetic rim lesion.
The paramagnetic rim is essentially an iron signature: a ring of iron-laden immune cells, known as activated microglia and macrophages, that form around the edge of a lesion.
“These paramagnetic rim signatures were initially seen in patients diagnosed with multiple sclerosis,” Dr. Lim notes.
In MS, brain lesions form when the immune system attacks myelin, triggering a burst of inflammation that usually settles. But in some lesions, the immune response persists. Iron-loaded cells remain gathered around the edges, continuing to slowly damage surrounding tissue long after the initial attack.
The paramagnetic rim, it turned out, marked this chronic, slow-burning inflammation that never fully resolves.
While researchers had already studied the paramagnetic rims in people with confirmed MS, Dr. Lim and Dr. Suthiphosuwan wanted to know whether the same marker showed up earlier in people who had brain lesions suggestive of MS, but no symptoms at all. This group of people is known as radiologically isolated syndrome, or RIS, which is the earliest detectable stage of MS.
The idea traced back to a pattern neurologists had already noticed in treatment. Hitting MS hard with high-efficacy drugs early on tended to produce better long-term outcomes than waiting and slowly escalating treatment as symptoms worsened.
Dr. Jiwon Oh, Medical Director of St. Mike’s BARLO MS Centre and the Waugh Family Chair in MS Research, supervised and guided the study as its senior and corresponding author. The research, supported throughout the years by the Barford, Love, and Waugh families, has enabled the team to follow people with RIS and investigate how MS begins and progresses.
“Using these advanced MRI measures helps us understand how MS starts and progresses,” Dr. Oh notes. “And these approaches will likely have a significant clinical impact on how we manage people with RIS.”
Dr. Lim and Dr. Suthiphosuwan’s latest study, guided by Dr. Oh, focused more closely on what those advanced MRI techniques could reveal, and which imaging markers proved most meaningful over time.
What the imaging data showed surprised even the team running the study. “The other established risk factors for this group of patients were supposed to predict who would go on to develop MS mostly didn’t hold up,” Dr. Lim says.
There was one striking exception: the paramagnetic rim lesion count was the one signal to more accurately predict who would go on to develop MS symptoms.
Even a single rim lesion raised risk. Though, as Dr. Lim and Dr. Suthiphosuwan note, the marker is specific rather than sensitive. This means that the absence of a rim lesion doesn’t rule out MS, but its presence is telling. One lesion alone raises risk by a few percentage points, the doctors note. The more meaningful threshold, drawn from MS research broadly, is four or more, at which point a patient’s prognosis shifts significantly. Patients who kept accumulating these lesions over time were the ones most likely to develop clinical symptoms.
That distinction matters because MS drugs aren’t risk-free, and treating every person with RIS “just in case” isn’t realistic. Recent studies have shown that starting disease-modifying therapy early can delay the onset of clinical MS, but only in patients who are actually going to need it.
Using these MRI markers in everyday care is becoming more realistic, Dr. Suthiphosuwan says. They are now included in the latest MS diagnostic guidelines, and the imaging sequences needed to detect them are becoming more widely available. BARLO’s clinicians are beginning to use these sequences in practice while refining when they can provide the greatest benefit to patients.
Publishing the study wasn’t straightforward either, the doctors say. The initial results, drawn entirely from the BARLO MS Centre, were strong, but they needed to prove that the findings held up elsewhere. That search for outside validation pushed the team to reach out to collaborators around the world, adding additional years to their research timeline.
“In a way, that makes the results much better,” Dr. Suthiphosuwan says, “Our results are the same around the world.”
This new research underscores the importance of BARLO’s current MRI refurbishments to enhance its imaging capabilities, an initiative made possible through extraordinary donor support. State-of-the-art MRI scanners will provide the image quality and advanced functionality needed to support regular follow-up for people with MS, while also creating new possibilities for research.
“As a radiologist, I see advanced MRI as essential to both patient care and discovery in MS,” Dr. Suthiphosuwan says. “With the right scanners and enough capacity, we can follow patients more closely, develop better techniques to diagnose MS, predict how the disease may progress, and measure whether treatments are working.”
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