Multiple sclerosis (MS) is the most common autoimmune disorder to affect the central nervous system. The body’s immune system attacks the myelin sheath surrounding nerve cells, slowing electrical signals and causing visual and sensorimotor deficits, cognitive decline and mood changes. Magnetic Resonance Imaging (MRI) plays a central role in the diagnosis of MS through the identification of plaques and active lesions, though MS can often only be definitively diagnosed when the number of lesions has been shown to increase over repeated examinations spanning months or years. Recently, functional MRI (fMRI) and Quantitative Susceptibility Mapping (QSM) have been shown to provide insights into the pathogenesis of MS and possible biomarkers of MS subtypes (relapsing-remitting (RR), primary progressive (PP) and secondary progressive (SP)). fMRI shows aberrant neuronal activation in response to motor tasks and changes to the motor resting state networks which are different in RR, PP and SP MS, for instance, whereas QSM provides images of the magnetic susceptibilities of different tissues, revealing iron deposits and demyelination.
A central objective of this project was the development of a new MRI method which allows functional (fMRI) and structural (QSM) data to be acquired simultaneously rather than in two separate scans. This drastically reduces the scan time. In the second stage of the project, the combined fMRI-QSM sequence has been used to examine, in different MS subtypes, reorganization of motor function and disruption of functional connectivity (from fMRI) in relation to the distribution of plaques, iron and demyelination (from QSM). This promises to allow MS to be diagnosed at an earlier stage, so that patients can begin treatment before damage accumulates. These new imaging methods will contribute to extending the healthy life expectancy of patients and reducing the burden on carers and health and support services.
