Magnetic resonance imaging of the cervical spinal cord in multiple sclerosis -: A quantitative T1 relaxation time mapping approach

Background The spinal cord is a common site of involvement in multiple sclerosis (MS) where pathology contributes substantially to locomotor disability. Previous studies have demonstrated significant correlations between clinical disability and cervical cord atrophy, but not with cord T-2 lesion load. We evaluate cervical cord pathology using, for the first time, quantitative T, relaxation time (T-1), which shows histopathological specificity for tissue damage in the cerebral white matter. Method Cervical cord IT, was compared in 15 MS patients [8 relapsing-remitting (RR), 7 secondary progressive (SP)] and 6 healthy controls, and related to normalised upper cervical cord area (UCCa), cerebral white matter T-1, T-2 lesion load and disability measures including the Expanded Disability Status Scale (EDSS), Ambulation index (AI) and timed 25-foot walk. T, maps of the brain and cervical cord were acquired using a high-resolution, 3-dimensional fast low-angle shot sequence. Dual-echo sequences were also obtained. Results Median cervical cord IT, [mean (standard deviation)] was significantly greater in RR [854 [28] ms] (p = 0.0006) and SP patients [927 [67] ms] (p < 0.0001) compared with controls [888 [61] ms], and in SP vs. RR patients (p = 0.002). In the overall patient cohort, it correlated significantly with median cerebral white matter T-1 (r = 0.7, p = 0.0046), UCCa (r = -0.87, p < 0.0001), but not T-2 lesion loads. Both median cervical cord T, and UCCa (respectively) correlated significantly with the EDSS (r = 0.55, p 0.03; r = -0.54, p 0.04), AI (r 0.77, p = 0.001; r = -0.60, p 0.02) and timed 25-foot walk (r = 0.56, p = 0.03; r = -0.55, p 0.04). Conclusion Cervical cord IT, distinguishes between MS subgroups and could also prove a useful surrogate outcome measure in MS. The relation of cervical cord IT, to cerebral white matter T, suggests that cord pathology may be influenced by tissue damage upstream.