Normal appearing white matter and tracts in patients with multiple sclerosis: susceptibility properties and clinical disability evaluation

Motivation: Magnetic susceptibility is influenced by myelin concentration, playing a significant role in the pathogenesis of MS as a demyelinating disease. Goal(s): This study aims to investigate normal-appearing-white-matter in MS patients using QSM, focusing on the cortico-spinal tract and optic radiation, to find non-invasive biomarkers of pre-clinical inflammatory activity. Approach: The automated implemented pipeline relies on the acquisition of multiple MR sequences. Several susceptibility histogram properties were considered and correlated with disability scores. Results: A decrease in myelin concentration was detected in MS group, consistently with the pathophysiology. Correlations between susceptibility and clinical disability occur, distinguishing clinical phenotypes and levels of motor impairment. Impact: Studying the normal-appearing-white-matter tracts using QSM reveals decrease in myelin concentration within cortico-spinal tract and optic radiation in MS patients. Variations were observed between different clinical phenotypes and various levels of motor impairment, suggesting biomarkers for early diagnosis and prognosis.