Differences in diffusion tensor imaging-derived metrics in the corpus callosum of patients with multiple sclerosis without and with gadolinium-enhancing cerebral lesions

OBJECTIVE: To analyze differences in corpus callosum diffusion tensor imaging metrics among patients with relapsing-remitting multiple sclerosis (MS) (RRMS) and secondary progressive MS (SPMS) with enhancing and nonenhancing cerebral lesions. METHODS: One-way analysis of variance and multiple linear regression models were used to assess the relationship between MS subtype, the presence of enhancing lesions, and fractional anisotropy (FA)/mean diffusivity (MD) values of the genu, body, and splenium of the corpus callosum from 22 patients with RRMS and 25 patients with SPMS. RESULTS: Analyses of variance: The subjects with SPMS with enhancing lesions had significantly lower genu and body FA values than those with nonenhancing SPMS and significantly lower genu, body, and splenium FA values than those with RRMS. Regression models: Enhancement was associated with decreased genu FA (P = 0.014). Secondary progressive MS was associated with decreased genu (P = 0.002) and splenium FA (P < 0.001) and significantly increased MD values. CONCLUSION: Patients with SPMS with enhancing lesions may be at increased risk for neuronal damage compared to nonenhancing SPMS and RRMS subtypes.