Magnetization transfer (MT) magnetic resonance imaging (MRI) can provide in vivo quantitative estimates of microscopic tissue damage in normal-appearing white matter (NAWM) and gray matter (GM) from patients with multiple sclerosis (MS).Objective
To determine whether a onetime MT MRI can provide markers of short-term disease evolution in patients with relapsing-remitting MS.Design
Eighteen-month observational study.Setting
Neuroimaging Research Unit, Scientific Institute and University Ospedale San Raffaele.Patients
Twenty-two patients with untreated relapsing-remitting MS.Main Outcome Measures
Relapse rate; disability according to the Expanded Disability Status Scale (EDSS); dual-echo, 2-dimensional gradient echo with and without a saturation MT pulse and T1-weighted MRIs of the brain; and MT ratio (MTR) histograms for NAWM and GM.Results
During the study period, 13 patients (59%) experienced 25 relapses. The median EDSS score was 1.25 (range, 0–3.5) at study entry and 1.75 (range, 0–3) at study exit. Significant, although moderate, correlations were found between average GM MTR values at baseline and EDSS changes during the study period (r = −0.44; P = .04). A trend was observed for the correlation between NAWM MTR values at baseline and the EDSS changes throughout 18 months (r = −0.42; P = .05). For the relation between EDSS changes and baseline GM MTR, the slope of the regression line was −0.5 (95% confidence interval, −1.0 to 0.0), indicating that a decrease in the baseline GM MTR of 1% predicted an increase in the EDSS score of 0.5 point throughout the 18 months.Conclusion
This study indicates that a “snapshot” MT MRI assessment detects subtle brain tissue changes that are associated with short-term disability accumulation in patients with relapsing-remitting MS.