Regional specificity of magnetization transfer imaging in multiple sclerosis

BACKGROUND: The goal of this study was to develop and validate a method for generation of regional magnetization transfer ratio (MTR). We also studied the topography of MTR changes in multiple sclerosis (MS) and in normal controls (NC), and preliminarily examined the clinical usefulness of this method. METHODS: We examined 45 patients with MS (relapsing remitting [RR] = 28 and secondary progressive [SP] = 17] and 19 NC. Mean disease duration was 14.3 years and median Expanded Disability Status Scale was 3.0. Regions of the brain were determined using semiautomated brain region extraction (SABRE). Twenty-six regional masks were automatically applied to MTR maps that were further split into gray matter (GM) and white matter (WM) compartments. RESULTS: Mean MTR from 12 SABRE regions differed significantly between MS patients and NC. For WM, all regional mean MTRs differed significantly between RR, SP, and NC participants (P <.001). In regression analysis, only 3 regions remained significantly different when corrected for total T2-LV. The regression model predicting disability selected GM mean MTR of the right medial inferior frontal region (P =.031). CONCLUSIONS: The study results showed that this regional MTR approach is reproducible, reliable and clinically relevant. MTI changes occur selectively in specific sub-regions.