Gray matter atrophy and disability progression in patients with early relapsing-remitting multiple sclerosis. A 5-year longitudinal study

We assessed the relationship between gray matter (GM) and white matter (WM) atrophy and clinical status in early relapsing-remitting multiple sclerosis (MS) patients over 5 years. A group of 181 patients who participated in the ASA (Avonex-Steroid-Azathioprine) study and had complete clinical and MRI assessments over 2 and 5 years was investigated. One hundred seventy (170) patients completed the 12-month follow-up, 147 the 24-month, 98 the 36-month, 65 the 48-month and 47 the 60-month. Changes in GM (GMV), WM (WMV) and peripheral GM (PGV) volumes, whole brain volume (percentage brain volume change PBVC), lateral ventricle volume (LVV), third ventricle width (3VW) and T2-lesion volume (T2-LV) were measured. Patients were assigned according to their clinical status to one of two groups: the Stable group, and the Reached Confirmed Sustained Progression (RCSP) group (24-week interval). At 0-6 months PBVC and GMV, at 0-12 months PBVC, GMV and T2-LV, at 0-24 months PBVC and GMV, at 0-36 months PBVC, GMV and T2-LV, and at 0-48 PBVC predicted the differences between the RCSP and Stable groups. PBVC and LVV showed the strongest ability to differentiate patients who presented 0 or ≥ 3 relapses in the Stable group. Decline in PBVC and GMV were predictive markers of disability deterioration. Correlation of T2-LV with clinical status was weaker and decreased over time. Higher number of relapses was associated with faster decline in whole brain volume.