Quantitative T2* Ferumoxytol MRI to Evaluate Activated Innate Immunity in Progressive Multiple Sclerosis

Motivation: Multiple sclerosis (MS) progression involves inflammation, microglia, and macrophage activation, contributing to axonal damage. Goal(s): This study investigates the utility of ferumoxytol-enhanced MRI for evaluating activated microglia and macrophages in progressive MS. Approach: . Nine secondary progressive MS patients underwent baseline and post-ferumoxytol 3T MRI scans, with T2* and ΔT2* maps computed to quantify ferumoxytol retention in lesions. Results: We successfully quantified ferumoxytol levels in ΔT2*-enhanced MS lesions in four subjects. In relapsing MS, newly formed active lesions typically contain a substantial number of macrophages, while chronic-active lesions in progressive MS predominantly exhibit microglia and macrophages in the perilesional areaImpact: These findings suggest ferumoxytol-enhanced MRI's potential for assessing microglia and macrophage activity in progressive MS, aiding accurate diagnoses and treatment. Clinicians could gain a valuable tool for monitoring disease progression, improving patient management and outcomes.