Dynamic changes of corticospinal tracts after stroke detected by fibertracking
- M Møller (moller{at}pet.auh.dk)
- J Frandsen (jesperf{at}pet.auh.dk)
- P Vestergaard-Poulsen (peterv{at}pet.auh.dk)
Abstract
Objectives: The integrity of motor pathways and functional connectivity patterns are important in assessing plastic changes related to successful recovery, to obtain prognostic information, and to monitor future therapeutic strategies of stroke patients. We tested the hypotheses; 1) that changes in axonal integrity along the corticospinal tract after stroke can be detected as a reduction of fractional anisotropy and 2) that sustained low fractional anisotropy is indicative of axonal loss, and therefore is correlated with poor motor outcome as measured by specific neurological motor scores.
Methods: We used magnetic resonance diffusion tensor imaging (DTI) in conjunction with 3D fiber tracking and specific neurological motor scores to test the hypotheses in five stroke patients within the first week and 30 and 90 days post-stroke.
Results: The results reveal that reduction in fractional anisotropy within the first weeks after stroke reflects decline of axonal integrity leading to Wallerian degeneration and demonstrate a correlation between the temporal evolution of fractional anisotropy and motor function in patients with poor motor outcome.
Conclusion: The study demonstrated the feasibility of fibertracking as a segmentation tool for mapping distal parts of the corticospinal motor pathways and showed that fractional anisotropy in the segmented corticospinal tract is a sensitive measure of structural changes after stroke.
