Fig. 4
Relationship between disease duration and brain volumes in MS with a disease duration of < 10 years. Scatter plots show the relationship between disease duration and brain volumes (NBV, NCGMV, NDGMV, normalized thalamic volume, or NWMV; a–e) in Japanese (black dots) and Caucasian patients (gray dots). The solid lines represent the linear regression of the data. A test of homogeneity of slopes showed significant differences in NBV (p = 0.02), NDGMV (p = 0.0002), and normalized thalamic volume (p < 0.0001) between the two groups. R2 = coefficient of determination