Cortical and Subcortical Morphometric and Iron Changes in Relapsing-Remitting Multiple Sclerosis and Their Association with White Matter T2Lesion Load: A3-Tesla Magnetic Resonance Imaging Study

IntroductionThis study was carried out to investigate the global and regional morphometric and iron changes in grey matter (GM) of multiple sclerosis (MS) patients and link them to the white matter (WM) lesions in amultimodal magnetic resonance imaging approach.Material and MethodsThe study involved 30 relapsing-remitting MS (RRMS) patients along with 30 age-matched healthy controls (HC) who were scanned on a3T Siemens Trio system. The scanning protocol included a3D, high resolution T1, T2, and T2*-weighted sequences. The T1-wimages were used in FreeSurfer for cortical reconstruction and volumetric segmentation, while T2-wimages were used to extract the WM T2 lesions; however, iron and magnetic susceptibility were calculated from the phase data of the T2*-wsequence. Surface-based analyses were performed in FreeSurfer to investigate the regional cortical morphometric changes and their correlations with the expanded disability status scale (EDSS), WM T2 lesions load, cortical iron deposition and magnetic susceptibility.ResultsSignificant differences were detected between the RRMS patients and HC for all cortical and subcortical morphometric changes. The EDSS and T2lesion load showed weak to moderate correlation with the reduced cortical morphometric measurements, increased cortical magnetic susceptibility and iron concentration. All deep grey matter (dGM) volumes showed asignificant strong positive correlation with the cortical surface area and volume in RRMS patients and HC.ConclusionsGrey matter is very much involved in the RRMS and cortical morphometric changes occur in anon-uniform pattern and are very likely to be associated with cortical iron deposition and magnetic susceptibility, dGM atrophy, WM T2lesion load, and disability.