Changes in Diffusion Tensor Eigenvalues in Corpus Callosum in Secondary Progressive Multiple Sclerosis: A Longitudinal DTI Study

Wei Tian¹, Tong Zhu¹, Jianhui Zhong¹, Xiang Liu¹, Praveen Rao², Benjamin M. Segal², Xiang Liu

A longitudinal DTI study was performed in 11 SPMS patients who completed 6 bimonthly MRI scans in one year. Based on the presence of T1 enhancing lesions during the study period, patients were divided into enhancing and non-enhancing groups. The enhancing group showed progressive FA decrease in body and splenium of corpus callosum (CC), accompanied significant elevation of radial diffusivity, but no obvious axial diffusivity change. No obvious temporal change of eigenvalues and FA was found in CC in the non-enhancing group. These findings revealed that the body and splenium part of CC were more vulnerable to damage than genu in SPMS. The radial diffusivity increase may contribute to FA reduction of CC in active progression compared to a more stable stage of the disease. DTI eigenvalues can provide valuable parameters for evaluating the severity, monitoring progression non-invasively, and exploring pathological functional pathways of SPMS in the future.