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The aim of the authors was: 1) to compare multicontrast cortical lesion detection using 3T and 7T MR imaging, 2) to compare cortical lesion type frequency in relapsing-remitting and secondary-progressive MS, and 3) to assess whether detectability is related to the magnetization transfer ratio, an imaging marker sensitive to myelin content. Multicontrast 3T and 7T MR images from 10 patients with relapsing-remitting MS and 10 with secondary-progressive MS were evaluated with the following 3T contrasts: 3D-T1-weighted, quantitative T1, FLAIR and magnetization-transfer, and 2D proton density- and T2-weighted. The following 7T contrasts were used: 3D-T1-weighted, quantitative T1, and 2D-T2*-weighted. Cortical lesion counts at 7T were the following: 720 total cortical lesions, 420 leukocortical lesions (58%), 27 intracortical lesions (4%), and 273 subpial lesions (38%). Cortical lesion counts at 3T were the following: 424 total cortical, 393 leukocortical (93%), 0intracortical, and 31 subpial (7%) lesions. Total, intracortical, and subpial 3T lesion counts were significantly lower than the 7Tcounts. The authors conclude that detection of leukocortical lesions at 3T is comparable with that at 7T MR imaging. Imaging at 3T is less sensitive to intracortical and subpial lesions.