Background: Conventional MRI lesion measures modestly predict long term disability in some CIS studies. Brain atrophy suggests neuroaxonal loss in MS with the potential to reflect disease progression to a greater extent than lesion measures.
Objective: To investigate whether brain atrophy and lesion load, during the first year in patients presenting with CIS, independently predict clinical outcome (development of MS and disability at 6 years).
Methods: Ninety-nine patients presenting with CIS were included in the study. T1 gadolinium-enhanced and T2-weighted brain MRI was acquired at baseline and approximately one year later. Percentage brain atrophy rate between baseline and follow-up scans was analyzed using SIENA.
Results: Mean annual brain atrophy rates were -0.38% for all patients, -0.50% in patients who had developed MS at six years and -0.26% in those who had not. Brain atrophy rate (p=0.005) and baseline T2LL (p<0.001) were independent predictors of CDMS. Whilst brain atrophy rate was a predictor of EDSS score in a univariate analysis, only one-year T2LL change (p=0.007) and baseline gadolinium-enhancing lesion number (p=0.03) were independent predictors of EDSS score at 6-year follow-up. T1 lesion load was the only MRI parameter which predicted MSFC score at the six year follow-up.
Conclusions: The findings confirm that brain atrophy occurs during the earliest phases of MS and suggest that one-year longitudinal measures of MRI change, if considered together with baseline MRI variables, might help to predict clinical status six years after the first demyelinating event in CIS patients, better than measurements such as lesion or brain volumes on baseline MRI alone.