Baseline MRI measures of lesion volume and brain atrophy predict distinct long-term clinical changes in patients with early multiple sclerosis (MS), according to a small study published online ahead of print July 23 in Multiple Sclerosis and Related Disorders.
The study identified several interesting potential biomarkers that are strongly associated with clinical worsening in early MS, said Amir-Hadi Maghzi, MD, postdoctoral research fellow at the University of California, San Francisco, and his associates.
The study included 43 patients with early MS, of whom 22 completed the three-year assessment. The patients had participated in a randomized, double-blind, placebo-controlled trial at two centers that assessed the possible neuroprotective effects of riluzole in combination with intramuscular interferon beta-1a. T2 lesion volume, as measured on MRI, significantly predicted longitudinal changes in the Paced Auditory Serial Addition Test, the authors reported.
In addition, three baseline measures of atrophy—brain parenchymal volume and normal-appearing white and gray matter volumes—predicted longitudinal changes in the MS Functional Composite score and the Timed 25-Foot Walk. The different findings for lesion and brain volume could reflect distinct disease processes, said the investigators.
Dr. Maghzi and his colleagues calculated longitudinal changes in brain volume by using the Structural Image Evaluation Using Normalization of Atrophy analysis. The researchers counted T2 and contrast-enhancing lesions by visualizing T2 and T1 images simultaneously before and after enhancement. Most MRI measures did not correlate with clinical outcomes at baseline, the researchers noted.
In longitudinal analyses, every 1% decrease in brain volume was associated with a 1.14-point decrease on the Symbol Digit Modalities Test (SDMT). For patients with MS, a four- to five-point decrease in SDMT score is associated with job loss, according to the authors. For every 1% decrease in brain volume, low-contrast letter acuity also declined by an average of nearly 1.5 letters, the investigators said.
—Amy Karon