Local tissue damage assessed with statistical mapping analysis of brain magnetization transfer ratio: relationship with functional status of patients in the earliest stage of multiple sclerosis.

BACKGROUND AND PURPOSE In the early stage of Multiple Sclerosis (MS), conventional MR imaging parameters such as T2 lesion load fail to explain the clinical status of patients. In the present work, we aimed to determine the ability of magnification transfer imaging to better reflect the relationship between local tissue damage and functional status of MS patients. METHODS We performed a comparative statistical mapping analysis on brain tissue magnetization transfer ratio (MTR) data measured in 18 patients with clinically isolated syndrome suggestive of MS (CISSMS) and 18 matched control subjects. RESULTS In the patients with CISSMS, a pattern of significant low MTR values was observed in the white matter, corpus callosum, bilateral occipitofrontal fascicles, right fornix, right parietal white matter, external capsule, right superior longitudinal fasciculus (SLF), right inferior longitudinal fasciculus, optica radiata, parietal white matter, right cingulum, gray matter, bilateral thalamus, bilateral caudate, right insula, and left Brodmann area (BA) 8. No correlation was found between local MTR decrease and Expanded Disability Status Scale score. Significant correlations between MTR and MS Functional Composite scores (Spearman rank test, P <.05) were observed in the left BA40, right SLF, right frontal white matter, splenium, and anterior corpus callosum. Local MTR values correlated with Paced Auditory Serial Addition Test scores in the left BA40, right BA4, right SLF, and splenium. CONCLUSION Statistical mapping analysis of brain MTR data provides valuable information on the relationship between the location of brain tissue damage and its functional impact in patients with MS, even in the earliest stage of the disease.