Relationship of Recovery of Contralesional Ankle Weakness With the Corticospinal and Corticoreticular Tracts in Stroke Patients

OBJECTIVE: We investigated the relationship between contralesional ankle weakness recovery and the corticospinal tract and corticoreticular tract in stroke patients with complete injuries of the ipsilesional corticospinal tract and corticoreticular tract. DESIGN: Thirty-six patients with complete injuries of the ipsilesional corticospinal tract and corticoreticular tract were recruited. Medical Research Council and the Functional Ambulation Category were used to determine motor function of ankle dorsiflexor and gait function. Patients were assigned into two groups: group A (poor recovery) and group B (good recovery). Fractional anisotropy, apparent diffusion coefficient, and tract volume were obtained for diffusion tensor imaging parameter. RESULTS: A total of 58.3% of patients showed good recovery of contralesional ankle dorsiflexor weakness, with remainder having poor recovery. Tract volume of the contralesional corticoreticular tract in group B was higher than that in group A (P < 0.05); no other diffusion tensor imaging parameters were significantly different between two groups. Tract volume of the contralesional corticoreticular tract and corticospinal tract showed strong (r = 0.521) and moderate (r = 0.399) positive correlations with Medical Research Council score of contralesional ankle dorsiflexor, respectively (P < 0.05). CONCLUSIONS: We found that the number of fibers of the contralesional corticospinal tract and corticoreticular tract was closely related to the recovery of contralesional ankle dorsiflexor weakness in stroke patients with complete injuries of the ipsilesional corticospinal tract and corticoreticular tract. Moreover, the contralesional corticoreticular tract had a closer relationship to recovery than the contralesional corticoreticular tract.