Characterization of differences between multiple sclerosis and normal brain: A global magnetization transfer application

BACKGROUND AND PURPOSE: Although the exact nature of the physiological diff erences between normal and multiple sclerosis (MS) brains are unknown, it h as been shown that their global magnetization transfer ratio (MTR) values a re significantly different. To more fully understand these differences, we examined MTR values by using 30 distinct measures. We provide a unique illu stration of these differences through a derived normal-to-MS transform. METHODS: Global MTR values for the group of normal subjects and for the gro up of MS subjects were characterized by 30 different measures involving sim ple statistics, histographic characteristics, MTR order information, and MT R range information. The measures that were significantly different with re spect to these two groups were discovered. From the mean MTR histogram of t he two groups, a transform was created to describe a conversion between the two brain states. Normal data were passed through this transform, creating a set of pseudo-MS data. The measures that were significantly different fr om the normal and pseudo-MS data were also obtained in order to verify the accuracy of the transform. RESULTS: Seventeen of the 30 measures were determined to be significantly d ifferent when comparing the sets of normal and MS data. The same set of 17 measures were found to be significantly different when comparing the normal and pseudo-MS data. CONCLUSION: The differences in the global MTR values of normal and MS subje cts are statistically significant compared with a large number of measures (alpha = 0,05). A normal-to-MS transform is a novel method for illustrating these differences.