3T magnetic resonance imaging relaxometry detects T2 prolongation in the global and regional brain normal-appearing white matter in multiple sclerosis

• Published in: Multiple sclerosis 2008-09, Vol.14, p.S213-S213
• Main Authors: Neema, M, Goldberg-Zimring, D, Guss, Z D, Healy, B, Houtchens, M, Weiner, H L, Alsop, D, Bakshi, R
• Format: Article
• Language: English
• ISSN: 1352-4585

Background: 3T magnetic resonance imaging (MRI) boosts the sensitivity in detection of overt multiple sclerosis (MS) brain lesions, but its role in detecting damage in the normal-appearing white matter NAWM) has not been established. Objective: To assess the ability of 3T MRI-based relaxometry to detect T2 prolongation in NAWM in MS. Methods: We tested if 3T MRI R2 relaxometry detected damage in NAWM of MS patients (n=13) vs. age-matched normal controls (NL) (n=11). Baseline characteristics of the MS group were: age (mean SD) 42.5 plus or minus 5.4 (range 33-51 years), disease duration 9.0 plus or minus 6.3 (range 1-22 years), expanded disability status scale (EDSS) score 2.5 plus or minus 1.7 (range 1-6.5), 11 relapsing-remitting, one primary progressive and one secondary progressive. R2 (1/T2) brain maps, created from 3T axial images at two spin echo times, were segmented to derive global and regional (region-of-interest-derived) cerebral R2 histograms of the NAWM. The regional NAWM areas were frontal lobe, parietal lobe, pons and the callosal splenium and genu. Results: Mean NAWM R2 relaxation rate was lower (indicating T2 prolongation) in MS than NL in the whole brain (p=0.00047), frontal lobe (p=0.00023), parietal lobe (p=0.0088) and callosal genu (p=0.0026). Similarly, R2 histogram peak position was lower in NAWM in MS than NL in the whole brain (p=0.019), frontal lobe (p=0.0011), callosal genu (p=0.0034) and splenium (p=0.034). No significant correlation with clinical characteristics was found with any of the R2 histogram metrics in this small sample. We continue to accumulate additional subjects to confirm and extend these findings. Conclusions: 3T MRI R2 relaxometry can detect tissue damage in the global and regional cerebral NAWM of MS patients that is missed by conventional lesion measures. Such findings may represent demyelination, inflammation and/or axonal loss.