To investigate clinical associations of paramagnetic lesion rims using 3T MRI in multiple sclerosis.

Paramagnetic rims (PR) have been observed as a feature of some MS lesions on susceptibility-weighted (T2*) MRI, and are thought to represent compartmentalized intrathecal inflammation.

This is a retrospective analysis of patients at a single neuroimmunology clinic.  All patients underwent standardized 3T MRI using a multiecho T2* GRE sequence with susceptibility postprocessing (SWAN protocol, GE).  SWAN phase maps and corresponding FLAIR images were manually reviewed by a rater (CH) initially blinded to clinical data, and iron rims determined based on qualitative assessment of T2* paramagnetic edges on corresponding T2-hyperintense lesions. We used descriptive statistics, t-tests, and chi squares to compare clinical and biological variables with the presence/absence of 1 or more PR. 

Seventy-one MS patients were included in this analysis (N=62 relapsing; 9 progressive). Baseline mean age was 49.5 years, disease duration 10.3 years, and mean EDSS 2.7, with 79% women. 86% were receiving a disease-modifying therapy; 30 patients (42%) had available cerebrospinal fluid (CSF) analysis. 35 of 71 MS patients (49%) had at least 1 PR. PRs did not vary by sex or EDSS but were associated with a younger age in this cohort (53.0 vs 45.8 years; p<0.01). PRs were strongly associated with the presence of CSF oligoclonal bands (OCB, chi²=9.13; p=0.003); all cases with at least 1 PR (N=15; 50%) had 2 or more unique OCB; 8 cases with OCB (27%) did not have evidence of a PR. We did not find any associations with PR and quantitative MRI parameters including whole brain volume or subsequent brain atrophy rates (all p<0.05).

The presence of at least one paramagnetic rim has a very high specificity but only modest sensitivity for presence of oligoclonal bands in the CSF.