Longitudinal clinical study of patients with iron rim lesions in multiple sclerosis

Abstract

Background: Iron rims (IRs) surrounding white matter lesions (WMLs) are suggested to predict a more severe disease course. Only small longitudinal cohorts of patients with and without iron rim lesions (IRLs) have been reported so far. Objective: To assess whether the presence and number of IRLs in patients with clinically isolated syndrome (CIS) and multiple sclerosis (MS) are associated with long-term disability or progressive disease. Methods: Ninety-one CIS/MS patients were recruited between 2008 and 2013 and scanned with 7 T magnetic resonance imaging (MRI). Expanded Disability Status Scale (EDSS) was used to calculate Age-related Multiple Sclerosis Severity Score (ARMSS) at the time of scan and at the latest clinical follow-up after 9 years. WMLs were assessed for the presence of IRL using Susceptibility weighted imaging (SWI)-filtered phase images. Results: In all, 132 IRLs were detected in 42 patients (46%); 9% of WMLs had IRs; 54% of the cohort had no rims, 30% had 1–3 rims and 16% had ⩾4. Patients with IRL had a higher EDSS and ARMSS. Presence of IRL was also a predictor of long-term disability, especially in patients with ⩾4 IRLs. IRLs have a greater impact on disability compared to the WML number and volume. Conclusion: The presence and number of perilesional IR on MRI hold prognostic value for long-term clinical disability in MS.

Lesion-level correspondence and longitudinal properties of paramagnetic rim and slowly expanding lesions in multiple sclerosis

“…9,15 PRLs represent a more destructive lesion phenotype and have been observed in patients with relapsing and progressive disease; increased PRL counts are correlated with greater T2-lesion burden and reduced brain volume, and may provide prognostic value for long-term disability. 9,17,18…”

“…9,15 PRLs represent a more destructive lesion phenotype and have been observed in patients with relapsing and progressive disease; increased PRL counts are correlated with greater T2-lesion burden and reduced brain volume, and may provide prognostic value for long-term disability. 9,17,18 Slowly expanding lesions (SELs), as defined on brain MRI, have also emerged as a potential in vivo marker of CALs, detectable on longitudinal T1-weighted (T1w) and T2-weighted (T2w) MRIs. 14 SELs are observed in all clinical subtypes of MS and represent a subset of non-enhancing T2-lesions with greater microstructural damage and ongoing demyelination and/or axonal loss over time.…”

Advances in Magnetic Resonance Imaging in Multiple Sclerosis

“…Supporting the view of the destructive nature of SEL, a 9-year follow-up study showed EDSS score worsening over the follow-up period in patients with ≥4 SELs and lower baseline MTR in SELs [47]. Another study showed worse EDSS and ARMSS (age-related multiple sclerosis severity) at 10 years follow-up in patients with ≥4 IRL [48] (Figure 5). Conversion to SPMS and higher EDSS at 9 years follow-up was associated with lower baseline MTR of SELs and higher T1 signal intensity decline in SELs at 2 years follow-up when compared with baseline, reflecting the contribution of the degree of microstructural tissue damage to the degree of future disability [47].…”

Paramagnetic rim lesions predict greater long-term relapse rates and clinical progression over 10 years

“…Our results confirm and extend previously reported associations between PRLs and longitudinal EDSS increases with a larger cohort, longer overall follow-up times, a much greater number of clinical visits, and with the assessment of T2-LV as a potential confounding factor. 9–11…”

“…[5][6][7] Several studies have evaluated the predictive value of PRLs on disease progression and reported encouraging results, but their findings have been limited by short follow-up periods (median of less than 5 years), small sample sizes (as low as eight people with MS (pwMS)), or have found weak predictive value of PRLs on disability progression. [8][9][10][11][12][13] Therefore, it remains unclear whether PRLs are a biomarker for a more aggressive disease course over timeframes relevant to long-term disease progression (e.g. 10 years).…”