Abstract

Objective: To investigate longitudinal changes with the novel iron-sensitive MRI measure quantitative susceptibility mapping (QSM), in multiple sclerosis (MS) and healthy controls (HCs) over a 2-year period. Background: Multiple sclerosis (MS) is a demyelinating neurodegenerative disorder where increased iron levels are known to be disturbed, especially in the deep gray matter (DGM). No longitudinal MRI studies using QSM have been conducted to investigate the temporal evolution of brain iron in MS. Methods: 160 participants were included, consisting of 120 MS patients and 40 age and sex-matched HCs. All participants were imaged using the same gradient echo sequence at both baseline and follow-up with the same 3T scanner. QSM susceptibility was determined for individual DGM structures, with an increase in susceptibility being representative of higher iron levels. Temporal (baseline to follow-up) and cross-sectional (MS vs HC) differences were tested using Mixed Factorial ANOVA analysis. Results: At either time-point, MS patients had significantly lower susceptibility in the thalamus (p<.001), but higher susceptibility in the caudate nucleus (p<.001) and globus pallidus (p<.001). Over 2 years, there was a trend for decreasing susceptibility in the thalamus in MS patients (p=.096), while susceptibility increased significantly in the caudate of both HC and MS (p=.012 and p=.003, respectively). EDSS change over two years was significantly correlated with higher DGM susceptibility (p=.027). Conclusion: In this novel longitudinal QSM study in MS, we show that magnetic susceptibility, indicative of iron levels, remained relatively steady in both HCs and MS patients, except in the caudate nucleus where susceptibility was significantly increased over time. MS patients had significantly higher susceptibility in the caudate nucleus and globus pallidus, and lower susceptibility in the thalamus. Increase in susceptibility was related with progression of disability, highlighting the potential of using QSM to monitor disease progression. Disclosure: Dr. Hagemeier has nothing to disclose. Dr. Schweser has nothing to disclose. Dr. Dwyer has received personal compensation for activities with Claret Medical and EMD Serono. Dr. Polak has nothing to disclose. Dr. Bergsland has nothing to disclose. Dr. Weinstock-Guttman has received personal compensation for activities with Biogen Idec, Teva Neurosciences, EMD Serono, Pfizer, Novartis, Genzyme & Sanofi, Mylan, and Acorda. Dr. Zivadinov has received personal compensation for activities with Teva Neuroscience, Biogen Idec, EMD Serono, Novartis, Claret Medical Inc., and Genzyme Corporation as a speaker and/or consultant.