Influence of CNS T2-focal lesions on cervical cord atrophy and disability in multiple sclerosis.

BACKGROUND: Mechanisms associated with cervical spinal cord (CSC) and upper thoracic spinal cord (TSC) atrophy in multiple sclerosis (MS) are poorly understood. OBJECTIVE: To assess the influence of brain, CSC and TSC T2-hyperintense lesions on cord atrophy and disability in MS. METHODS: Thirty-four MS patients underwent 3T brain, cervical and thoracic cord magnetic resonance imaging (MRI) and Expanded Disability Status Scale (EDSS) score assessment. CSC/TSC lesion number and volume (LV), whole-brain and cortico-spinal tract (CST) LVs were obtained. Normalized whole CSC and upper TSC cross-sectional areas (CSAn) were also derived. Age- and sex-adjusted regression models assessed associations of brain/cord lesions with CSAn and EDSS and identified variables independently associated with CSAn and EDSS with a stepwise variable selection. RESULTS: CSC CSAn (ß = -0.36, p = 0.03) and TSC CSAn (ß = -0.60, p < 0.001) were associated with CSC T2 LV. EDSS (median = 3.0) was correlated with CSC T2 LV (ß = 0.42, p = 0.01), brain (ß = 0.34, p = 0.04) and CST LV (ß = 0.35, p = 0.03). The multivariate analysis retained CSC LV as significant predictor of CSC CSAn (R2 = 0.20, p = 0.023) and TSC CSAn (R2 = 0.51, p < 0.001) and retained CSC and CST LVs as significant predictors of EDSS (R2 = 0.55, p = 0.001). CONCLUSIONS: CSC LV is an independent predictor of cord atrophy. When neurological impairment is relatively mild, central nervous system (CNS) lesion burden is a better correlate of disability than atrophy.