Magnetic resonance imaging correlates of clinical outcomes in early multiple sclerosis.

Objectives: To study the association between changes in brain magnetic resonance imaging (MRI) and clinical outcomes in early MS.

Methods: MS patients within 12 months of onset were enrolled and followed up to 3 years. Clinical measures included Symbol Digit Modalities Test (SDMT), MS Functional Composite (MSFC) and low contrast letter acuity (LCLA). MRI outcomes included brain volume changes measured by SIENA and SIENAX normalized measurements [brain parenchymal volume (BPV), normal-appearing white and gray matter volume (NAWMV and GMV) and T2 lesion volume (T2LV)]. Mixed model regression measured time trends and associations between imaging and clinical outcome.

Results: Forty-three patients were enrolled within 7.5±4.9 months of onset. Baseline T2 lesion volume predicted subsequent changes in Paced Auditory Serial Addition Test (PASAT) (p=0.004), whereas baseline measures of atrophy including BPV, GMV, and NAWMV predicted longitudinal changes in MSFC (p=0.016, p=0.040, p=0.021, respectively) and Timed-25 Foot Walk (p<0.05). Each 1% decrease in SIENA was associated with 1.14 point decrease in SDMT score (p=0.03). Each 1% decrease in brain volume SIENA was associated with almost 1.5 letters decrease on LCLA (p=0.02).

Conclusion: Measures of lesion volume and overall brain volume were associated with different long-term clinical outcome measures in early MS.