A comparison between magnetization transfer ratios and myelin water percentages in normals and multiple sclerosis patients.

Magnetization transfer and T2 relaxation data were obtained for five white and six gray matter brain structures from 10 normal volunteers and 9 multiple sclerosis patients. Thirty MS lesions were also analyzed. Magnetization transfer ratios and myelin water percentages were compared. Both techniques showed a significant difference between the average of white and gray matter of the normal volunteers as well as the average of normal-appearing white matter and gray matter of the multiple sclerosis patients. The average magnetization transfer ratio and myelin water percentage for lesions were significantly lower than those of normal-appearing white matter. Myelin water percentages and magnetization transfer ratios were uncorrelated in white and gray matter but showed a small (R = 0.5, P = 0.005) but significant correlation in multiple sclerosis lesions. In summary, the myelin water percentage and the magnetization transfer ratio provide quantifiable but largely independent measures of multiple sclerosis lesion pathology.