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WEST PALM BEACH, Fla. -- Paramagnetic rim lesions (PRLs) predicted cognitive decline in multiple sclerosis (MS), data from a longitudinal cohort study showed.

At year 4, scores on the Symbol Digit Modalities Test (SDMT), a measure of cognitive processing speed, were lower for MS patients with at least one baseline PRL compared with those who had no baseline PRLs, reported Hannah Schwartz, a clinical research coordinator at Weill Cornell Medicine in New York City, during the Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) Forum.

In a multivariate model, people with at least one PRL at baseline had average adjusted SDMT scores that were 4.1 points lower at year 4 than patients without a PRL (P=0.028). The is a 90-second timed test; scores range from 0 to 110, with higher scores indicating faster processing.

"Paramagnetic rim lesions may identify patients who are at risk of a more aggressive disease course, specifically in terms of cognitive decline," Schwartz said. "There is considerable research around developing prognostic biomarkers for MS, and our results are a first step toward the possibility of applying these PRLs in a clinical setting."

While cross-sectional studies have demonstrated an association between PRLs and worse cognitive functioning, there's limited data about future cognitive impairment, she added.

MRI traditionally has been used to detect new lesions in MS, noted co-author Susan Gauthier, DO, MPH, also of Weill Cornell Medicine. As a result, chronic lesions or scars are often overlooked.

"However, recent studies have shown that some chronic lesions exhibit ongoing inflammation at their rims, indicating persistent immune activity that could cause further damage," Gauthier told 番茄社区. "Paramagnetic rim lesions, a type of chronic active lesion, contain iron within the immune cells at their rim, making them detectable via MRI."

"Our study adds to evidence that paramagnetic rim lesions are associated with a more aggressive disease progression," she added. "With MRI's ability to identify paramagnetic rim lesions, there's a concerted effort to leverage this imaging biomarker in clinical practice, potentially revolutionizing the use of MRI for patient care."

The study included 106 MS patients with MRI and cognitive data from an ongoing longitudinal study. Schwartz and co-authors used quantitative susceptibility mapping, a post-processing imaging technique, to identify PRLs on imaging. Other imaging variables included T2 fluid attenuated inversion recovery (FLAIR) total lesion volume, cortical thickness, lesion myelin water fraction, and thalamic volume.

Baseline and 4-year cognitive evaluations were performed using the Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS), which includes the SDMT, California Verbal Learning Test-II (CVLT), and the Brief Visuospatial Memory Test-Revised (BVMT).

Univariate linear models assessed the relationship between baseline imaging features and cognitive function at year 4. Multiple linear models were performed with all possible variables and final models were determined based on significant variables only.

Of the 106 study participants, 73.6% were female. Mean baseline age was about 43. Nearly all patients (92.5%) had relapsing-remitting MS, and most (69.8%) were on highly effective disease-modifying treatment. At baseline, 38.7% had at least one PRL, and the mean Expanded Disability Status Scale () score was 1.0, indicating minimal disability.

Patients with PRLs performed worse on all cognitive tests, Schwartz said. In the univariate model, the gap between PRL and no-PRL groups widened at 4 years, although only SDMT reached significance.

In a separate multivariate model, BVMT scores at year 4 were associated with the presence of PRLs when controlling for baseline BVMT and disease duration. Participants with at least one PRL at baseline had an average BVMT score that was 1.9 points lower at year 4 than patients without a PRL (P=0.042). There was no relationship between PRLs and CVLT at year 4.

Other MRI variables tied to subsequent cognitive function included overall lesion myelin damage (which was linked with SDMT), and total lesion volume (which was associated with CVLT).

The study had several limitations, Schwartz acknowledged: the cohort was small and imaging data were available only at baseline. BICAMS is a limited cognitive assessment, she added.

"We would want large, multicenter studies to replicate this result to evaluate the full potential of PRLs as an imaging biomarker to identify patients at risk for cognitive decline," she said. "We might be able to treat them more aggressively to preserve their cognition."

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