ABSTRACT
Objective To investigate the changes of the cervical spinal cord in patients with relapsing-remitting multiple sclerosis (RRMS) and relapsing neuromyelitis optica (RNMO) using diffusion tensor imaging (DTI) and to analyze its correlations with clinical disability scores.Methods Thirty patients with MS (MS group),28 patients with NMO (NMO group) and 20 healthy volunteers were imaged using DTI on a 3.0 Tesla scanner.DTI indices of cervical spinal cord from all participants were measured,including mean diffusivity (MD) and fractional anisotropy (FA),and the correlations between the DTI metrics and the expanded disability status scale (EDSS) scores were assessed.One-way ANOVA,Dunnett-t test and Spearman correlation analysis were used for statistics.Results (1) The values of MD among three groups were different at C3 level for left lateral and dorsal columns,C4 level for the central gray substance and dorsal columns,and C5-C6 level for all structures.There were significant differences among them (F =4.006-36.814,P ＜ 0.05).The values of FA were significantly different at all levels (F =5.561-98.128,P ＜0.05).(2) Compared with the control group,the values of MD were increased and FA were decreased for both MS and NMO groups,there were significant differences among them (t =-0.320-3.138,P ＜0.05).In MS and NMO groups,there were no significant differences of MD (t =-1.183-0.069,P ＞0.05),while the FA at C4-C6 levels (including the central gray substance,dorsal columns,right lateral columns and left lateral columns) for NMO group were 0.57 ± 0.09,0.56 ± 0.11,0.54 ±0.10,0.57±0.09,0.55 ±0.11,0.52 ±0.13,0.55 ±0.11,0.54 ±0.13,0.54±0.10,0.54±0.11,0.53 ±0.13,0.52 ±0.11 ;and for MS group were 0.67 ±0.10,0.68 ±0.10,0.68 ±0.10,0.70 ±0.12,0.68 ±0.11,0.69±0.10,0.68 ±0.11,0.69 ±0.12,0.67 ±0.14,0.68 ±0.15,0.69 ±0.14,0.69 ±0.16,and there were significant differences between two groups (t =-0.011-0.169,P ＜ 0.05).(3)Univariate correlations between DTI measures and the average EDSS scores were assessed.The MD at all levels showed significant positive correlations with disability scores (r =0.324-0.541,P ＜ 0.05),and FA significant negative correlated with disability scores (r =-0.632--0.294,P ＜ 0.05),except C4 level for lateral columns and C2 level.Conclusions DTI metrics are sensitive to cervical spinal cord damage in demyelinating diseases,providing an important way of distinguishing MS from NMO,and can be potentially useful quantitative biomarkers for monitoring the evolution of demyelinating diseases.