Axial diffusivity changes in the motor pathway above stroke foci and functional recovery after subcortical infarction

BACKGROUND Secondary degeneration of the fiber tract of the motor pathway below infarct foci and functional recovery after stroke have been well demonstrated, but the role of the fiber tract above stroke foci remains unclear. OBJECTIVE This study aimed to investigate diffusion changes in motor fibers above the lesion and identify predictors of motor improvement within 12 weeks after subcortical infarction. METHODS Diffusion tensor imaging and the Fugl-Meyer (FM) scale were conducted 1, 4, and 12 weeks (W) after a subcortical infarct. Proportional recovery model residuals were used to assign patients to proportional recovery and poor recovery groups. Region of interest analysis was used to assess diffusion changes in the motor pathway above and below a stroke lesion. Multivariable linear regression was employed to identify predictors of motor improvement within 12 weeks after stroke. RESULTS Axial diffusivity (AD) in the underlying white matter of the ipsilesional primary motor area (PMA) and cerebral peduncle (CP) in both proportional and poor recovery groups was lower at W1 compared to the controls and values in the contralesional PMA and CP (all P