A longitudinal MRI study of cervical cord atrophy in multiple sclerosis.

There is an urgent need of fast and accurate methods for the longitudinal quantification of cervical cord atrophy in multiple sclerosis (MS). Aim of this study was to compare a new semi-automatic method [the active surface (AS) method] with an existing cord segmentation method (the Losseff method) to measure cervical cord atrophy progression in MS patients. Using the AS and Losseff methods, normalized cervical cord cross-sectional area (CSA) was compared between 35 MS patients and 9 healthy controls (HC) at baseline and after 2.3 years of follow-up. Correlations with clinical/conventional MRI variables and a power calculation study were also performed. At follow-up, the Losseff method detected a 1 % CSA increase in HC and a 3.5 % decrease in MS patients (p = 0.01), while the AS method detected a 0.1 % decrease in HC and 3 % decrease in MS patients (p = 0.02). The AS method was more sensitive to associations with disability/conventional MRI variables and also provided lower numbers of subjects per arm compared to the Losseff method in a putative clinical trial scenario. Cord AS CSA measurements were more sensitive to longitudinal changes in MS patients than Losseff measurements. Cord AS CSA might be a valuable surrogate outcome measure for monitoring neuroprotection in MS.