Spatial correlation of pathology and perfusion changes within the cortex and white matter in multiple sclerosis

Abstract

Backgroundandpurpose: The spatial correlation betweenWMand corticalGMdisease in multiple sclerosis is controversial and has not been previously assessed with perfusion MR imaging. We sought to determine the nature of association between lobar WM, cortical GM, volume and perfusion. MATERIALS AND METHODS: Nineteen individuals with secondary-progressive multiple sclerosis, 19 with relapsing-remitting multiple sclerosis, and 19 age-matched healthy controls were recruited. Quantitative MR perfusion imaging was used to derive CBF, CBV, and MTT within cortical GM, WM, and T2-hyperintense lesions. A 2-step multivariate linear regression (corrected for age, disease duration, and Expanded Disability Status Scale) was used to assess correlations between perfusion and volume measures in global and lobar normalappearing WM, cortical GM, and T2-hyperintense lesions. The Bonferroni adjustment was applied as appropriate. RESULTS: Global corticalGMandWMvolume was significantly reduced for each group comparison, except corticalGMvolume of those with relapsing-remitting multiple sclerosis versus controls. Global and lobar cortical GM CBF and CBV were reduced in secondaryprogressive multiple sclerosis compared with other groups but not for relapsing-remitting multiple sclerosis versus controls. Global and lobarWMCBF and CBV were not significantly different across groups. The distribution of lobar corticalGMandWMvolume reduction was disparate, except for the occipital lobes in patients with secondary-progressive multiple sclerosis versus those with relapsing-remitting multiple sclerosis. Moderate associations were identified between lobar cortical GM and lobar normal-appearingWMvolume in controls and in the left temporal lobe in relapsing-remitting multiple sclerosis. No significant associations occurred between cortical GM andWM perfusion or volume. Strong correlations were observed between cortical-GM perfusion, normal appearing WM and lesional perfusion, with respect to each global and lobar region within HC, and RRMS and SPMS patients (R 2 ≥ 0.96, P < .006 and R 2 > 0.738, P