Magnetization transfer MRI: Application to treatment of middle cerebral artery occlusion in rat

The temporal profiles of MRI parameters which use quantitative estimates of magnetization transfer were measured in 22 male Wistar rats subjected to m iddle cerebral artery occlusion, with and without therapeutic intervention with an anti-ICAM-1 monoclonal antibody. Two measures were used: the value of a magnetization transfer-related parameter in a predetermined region of interest, and the area of damage, as measured by changes in this parameter. In both groups, the value and area of damage of the Inverse of the apparen t forward transfer rate for magnetization transfer (1/k(fa))significantly i ncreased from the preischemic values (P < 0.05), as did T-1 under an off-re sonance partial saturation of the macromolecular pool (T-1sat), and T-1 (P < 0.05). Moreover, the increase in the value and total area of damage, as m easured by 1/k(fa), T-1, and T-1sat in the treated group, was smaller compa red to that of the untreated group, with significant differences detected b etween groups at 5, 24, and 48 hours. Our data suggest that a quantitative measure of MT may provide a sensitive and early method to detect the effica cy of therapeutic intervention in experimental stroke. (C) 2001 Wiley-Liss, Inc.