One-dimensional-ratio measures of atrophy progression in multiple sclerosis as evaluated by longitudinal magnetic resonance imaging.

BACKGROUND

For decades, normalized one-dimensional (1D) measures have been used in the evaluation of brain atrophy. In multiple sclerosis (MS), the use of normalized linear measures over longitudinal follow-up remains insufficiently documented.

PURPOSE

To evaluate the association between different regional atrophy measures and disability in MS patients over four decades in a longitudinal cross-sectional study.

MATERIAL AND METHODS

37 consecutively selected MS patients were included. At baseline, patients had a range of disease duration (1-33 years) and age (24-65 years). Each patient was followed by magnetic resonance imaging (MRI) for a mean of 9.25 years (range 7.3-10 years). Four 1D measures were applied at three time points on axial 5-mm T1-weighted images. Three clinical MS subgroups were represented: relapsing-remitting MS (RRMS), secondary progressive MS (SPMS), and primary progressive MS (PPMS).

RESULTS

There were significant changes in all 1D ratios during follow-up. The Evans ratio (ER) and the bifrontal ratio (BFR) were associated with the development of disability. Changes of ER and BFR reflected more aggressive disease progression, as expressed by MS severity score (MSSS).

CONCLUSION

All four normalized ratios showed uniform atrophy progression, suggesting a consistent rate of atrophy over long-term disease duration independent of MS course. Disability status correlated with 1D measures, suggesting that serial evaluation of Evans and bifrontal ratios might contribute to the radiological evaluation of MS patients.