Differential Changes in Deep and Cortical Gray Matters of Patients With Multiple Sclerosis: A Quantitative Magnetic Resonance Imaging Study

摘要

Objective: The objective of our study was to evaluate the changes in quantitative diffusion tensor (DT) metrics and normalized T2-signal intensity (nT2-SI) values of normal-appearing cortical gray matter (CGM) and deep gray matter (DGM) in patients with multiple sclerosis (MS). Methods: Fifty patients with MS and 25 patients with no MS matched on sex/age were selected as controls. Conventional magnetic resonance imaging and DT imaging were performed. Fractional anisotropy (FA)/ mean diffusivity (MD) and nT2-SI values of CGM and DGM were measured. Analyses of variance between the 2 groups were analyzed; Pearson correlations between DT metrics and nT2-SI values and brain parenchymal fraction (BPF) and T2 lesion volumes (LVs) were used. Results: Patients with MS showed larger MD/smaller FA values in the CGM region compared with controls (P < 0.05). However, MD/FA values were not statistically significant in the DGM between MS and healthy control group, m DGM of MS patients, a significant decrease of nT2-SI values were observed when compared with controls (P < 0.05), but nT2-SI values in the CGM of MS patients showed no significant decrease, hi CGM, only MD values of frontal lobes in MS patients were significantly (negatively) correlated with BPF(right: P = 0.009, left: P = 0.036) or T2 LVs (right: P = 0.002, left: P = 0.047). Normalized T2-SI values in all DGM regions of MS patients were significantly correlated with BPF (r = 0.282-0.504, P < 0.05) except for the left thalamus and bilateral red nucleus. There was no correlation between nT2-SI in all DGM regions and T2 LVs of MS patients. Conclusion: In CGM, the change in quantitative DT metrics of MS patients and the association with BPF and T2 LVs suggest the existence of microstructural destruction corresponding to inflammation, demye-lination, or wallerian degeneration, but the changes in CGM were independent of the concomitant changes in BPF and T2 lesion. In DGM, a decrease of nT2-SI in MS patients and the correlation of nT2-SI values with BPF (brain atrophy) suggest excessive iron deposition related to chronic destruction. Our investigation indicates the possibility of different mechanism of pathological change in CGM and DGM.