Quantitative susceptibility mapping reveals widespread brain iron abnormalities in sporadic patients with early-stage amyotrophic lateral sclerosis.

In the present study, using the novel quantitative susceptibility mapping technique, we aimed to systematically investigate brain iron alterations in a large group of sporadic early-stage amyotrophic lateral sclerosis patients and their correlation with clinical disability. In this study, amyotrophic lateral sclerosis patients at King's stage 1 were defined as early-stage amyotrophic lateral sclerosis patients, and 53 newly diagnosed early-stage amyotrophic lateral sclerosis patients and 50 healthy controls were included. Voxel-based whole-brain quantitative susceptibility mapping analysis was used to explore brain iron alterations. Voxel-based morphometry analysis was also performed. Longitudinal follow-up was performed in amyotrophic lateral sclerosis patients, and the follow-up progression rate was calculated. We found that, compared with healthy controls, early-stage amyotrophic lateral sclerosis patients presented significantly increased susceptibility values, mainly in the motor cortex, prefrontal cortex, hippocampus and cerebellar regions, while volumetric alterations were not detected. Moreover, motor and extra-motor cortex susceptibility values were significantly correlated with upper motor neuron scores and follow-up progression rate (r = 0.452-0.504, P < 0.01) in early-stage amyotrophic lateral sclerosis patients. We demonstrated a clear profile of early motor and extra-motor iron depositions and their important roles in early-stage amyotrophic lateral sclerosis patients. We suggest that quantitative susceptibility mapping is likely a promising neuroimaging approach for assessing early upper motor neuron damage and detecting early extra-motor alterations in amyotrophic lateral sclerosis patients.