The following is a summary of “Characteristics, Prevalence, and Clinical Relevance of Juxtacortical Paramagnetic Rims in Patients With Multiple Sclerosis,” published in the December 2023 issue of Neurology by Galbusera et al.
Juxtacortical paramagnetic rims (JPRs), a potential marker of chronic inflammation in multiple sclerosis (MS), are being explored for their clinical relevance in a specific subgroup of MS patients.
Researchers launched a retrospective study to delve deeper into the clinical relevance of JPRs in vivo and their histologic underpinnings via postmortem MRI of fixed whole MS brains.
They screened 165 in vivo cohort patients with MS using Quantitative Susceptibility Mapping (QSM) and Magnetization-Prepared 2 Rapid Acquisition Gradient-Echo (MP2RAGE) images at 3T-MRI for JPRs and cortical lesions. Additionally, 3T-MRI was employed to image five postmortem brains from MS patients, capturing QSM and MP2RAGE sequences. Tissue blocks with JPRs underwent excision and were embedded in paraffin; subsequent immunohistochemistry involved staining for myelin essential protein (for myelin) and anti-CR3/43 (for MHC II-positive microglia/macrophages). Iron detection employed DAB-Turnbull stain.
The results showed JPRs in around 10% of in vivo patients, correlating with an elevated cortical lesion load. Among the 5 postmortem brains, 1 exhibited JPRs. Histologically, JPRs were aligned with the accumulation of activated iron-laden phagocytes linked to demyelination across the entire overlying cortical ribbon.
Investigators concluded that JPRs, a novel MS biomarker for focal cortical demyelination, are linked to global pathology and show clinical promise.